I really sympathize with you. My background is very similar. I too converted to Orthodoxy from Protestantism. I am currently a catechumen. My conversion story is linked below in case you are interested.http://www.orthodoxchristianity.net/forum/index.php/topic,42793.0.html
Personally, I think that you should NOT attend the Orthodox parish until you have everything else in check. Let me be honest with you; Orthodox services blow Protestant ones out of the water. I am saying this as a convert and I am not exaggerating. When I first attended an Orthodox service I never even wanted to return or go back to the Protestant ones ever again; I could not imagine it. They seemed so mediocre compared to Orthodoxy. Going back to a Protestant service after you have attended an Orthodox one is like going back to bologna after you have had the luxury of eating steak. Once you attend that Orthodox service for the first time, you are going to want to come back. Many a soul has been won over by the external worship.
I would say that the biggest thing which led to my conversion was the history. Through my research as a Protestant I learned that the Orthodox Church is the oldest Church, and I remembered how Jesus promised that He would protect His Church from Hell for all ages. This alone was the primary reason behind my conversion. It seemed that no Protestant had a valid explanation for this, and to me it seemed like the Protestants did not have faith in Jesus' promise to protect His true Church forever, and so I left Protestantism. I accepted all of the teachings of Orthodoxy on simple trust because I believed and still believe that Jesus will not allow heresy or evil to ever become a dogma of His true Church. I also began to learn about how obvious and well supported these beliefs were, and in contrast, how misinterpreted and to be honest, absurd, the beliefs of mainstream Protestantism are compared to it. When you become Orthodox, your mind set changes, and you begin to see things in ways you never have before, but in a good way mind you.
Moving forward, to answer your questions. I highly understand the hang-up with your family not accepting your conversion. I too deal with the same issue. I am sixteen years old and at the entire mercy of my radical Protestant parents but I still converted to Orthodoxy about six or eight months ago and they are not happy about it at all, but they are not stopping me. My piece of advice to you is to not let your family hold you down. There is always going to be opposition to the truth, but it is the truth no doubt, and we should not let hardships make us stray from the truth. At first, they are going to be all preachy trying to stop you from converting, but remain strong and steadfast. With knowledge and faith, always be prepared to refute and answer their doubts to Orthodoxy and stand up against their Protestant beliefs and criticisms. But do it in kindness and only do it when they are trying to turn you away from your faith. Do not go looking for a fight. And when you do not know the answer to something, do not be afraid to admit it, lest you accidently spit out heresy and classify it as Orthodox teaching.
After this stage, the preachiness will die out. And they will learn to tolerate you. My immediate family does not try to prach to me anymore or stop me. They just stay out of my religious life and I stay out of theirs. They do however get a bit offended when I publicly talk about my beliefs in front of them or tell my little brother about Orthodox beliefs. I've learned to keep my faith to myself, yet, still remain strong and to not give into their beliefs. Eventually, you will learn to do the same. People are going to be worried about offending you, and they may be uneasy around you to be honest. This is how Protestants have reacted around me after learning of my conversion. And, my next piece of advice to you is to try to be understanding and keep your cool. There are going to be many times when your Protestant friends are going to offend your faith, but many times it is actually going to be by ACCIDENT because they honestly do not know. In fact, sometimes they may accidently offend your faith when they are trying to be polite and sensitive about it!
For example, one time a Protestant friend of mine invited me to her 'non-denominational' Protestant Church, and I refused the offer, telling her it feels awkward for me since I'm an Orthodox Christain, and her response was 'We're non-denominational, don't worry!' and this highly offended me, because she was classifying Orthodoxy as a denomination even though we are the only non-denominational Church since we are the original, in fact, we are pre-denominational. But, she did not know this, and she was only trying to make me feel welcome. See what I mean? Try to understand that your Protestant associates are going to make mistakes, but we have to be forgiving and understanding of their ignorance and be kind, not quick to lose our cools.
Lastly, when they bring up arguments against Orthodoxy or doubts, do not be afraid! Most arguments against Orthodoxy from Protestants come from strawmen and misconceptions because most of them do not even know what we are! Or, they can be refuted with basic knowledge. It is not an exaggeration when I say that the most complex, deep Protestant argument or belief which came from years of intense theological study and revision can be refuted with even the most basic of Orthodox knowledge that the average layman can learn within the first year of their conversion.
I commend your interest into Orthodoxy and highly sympathize with you since I share a similar background. I would love to help, counsel or do anything I can to aid you! I assure you that once you attend an Orthodox service you will not be returning back to the Protestant ones. Feel free to message me or email me and may God bless your journey!