I am a 20-year-old male, and I also go to church alone mostly. When I began attending the Orthodox church I go to, it was alone, of my own volition and not out of rejection by anyone else who might go with me. After finding the church, I decided to just go, expecting to be awkward (not knowing the liturgy and being new to the people) and thus having the same fears that you have. I had the same fears and reservations, so I e-mailed the rector to make sure I would be welcome unannounced. He said, verbatim, "Don't worry, just come!" So I did, and, aside from not knowing "what to do" in the liturgy, it was incredibly rewarding.
I have, though, taken my mother with me several times, when I could (she has only Thursdays and Fridays off of work, no exception), and she is glad to when possible, to see the beauty of the churches and liturgy. As a result of my "awkward" attendance, nearly every member of the parish has taken it upon themselves to become acquainted with me, to find out who I am, why I visit, and most importantly, to urge me to keep returning so that they can get to know me better as part of the parish community. I get vocal "Welcomes," pats on the back and "Please visit again/more"s on top of big smiles and "Hello"s and every other gesture of acceptance. In a just a few weeks' time, there are but few regular practitioners who haven't taken the coffee hour after Divine Liturgy as an opportunity to sit next to me purposefully to see who I am and to talk (not about the Church, but what I do, how old I am, where I live, etc.); when in line for the after-liturgy lunch, the people in front and behind me start conversations, and the people fixing and serving the food act no different. The ones who haven't [yet] done anything of the sort are non-native-English-speakers who aren't comfortable (understandably) with many people at all other than the priest and Matushka and others of common language. The Matushka and priest were, of course, the first to beeline right to me to welcome me and introduce themselves, and I feel it to be the most beautiful community structure I've ever encountered. At the very large Greek Cathedral with many hundreds of members, the priest literally came right to me as a clearly new person and introduced himself and offered sweets and pastries from the offerings to the Theotokos on that particular feast day. I visited a church on the other side of the country (Boston) on vacation, and the priest knew I was new and welcomed me heartily, with a blessing and all. At the parish I now visit regularly, near every clergyman has at least patted me on the back and said "Welcome." But even in small towns in my state, I'm Just Another Brick in the Wall in the communions of the Roman Catholic parishes I've visited.
Though a loner in nature, I do try to acquaint with people and offer them common courtesy and respect, but in no community of any other type have I ever experienced the welcome offered by Orthodox faith communities.