I wouldn't get too down on it dude. You can definitely change that if you'd like. When i was younger, i had the same problem. Growing up with 5 brothers and 1 sister, i always seemed to fall into the shadows of my siblings, mainly because they're all older than me. I was always the very quiet one, didn't seem to care for socializing with others, unless they were people i already knew, cousins, some friends, etc. I, like you, had no problem socializing online, it felt like a completely different world for me, and made it quiet easy to speak my mind. It wasn't that i couldn't carry out a conversation, it's just that i didn't really care to.
It wasn't until about 18 when i got my first retail gig. That pretty much forced me to speak to strangers on a daily basis. I worked there for almost 5 years, so that constant communication allowed me to be a more open person. That pretty much set me on a path for new things. I met my wife in College, got married, had a kid, and have a pretty good job. Mostly because i taught myself to carry out random conversations, and fake interest in what people are talking about.
One of my brothers has had this issue as well, just on a bigger scale. He was consistently sheltered from a lot of things by my parents, so now he's having an issue with relationships. He's got a great job, great work ethic, but no social skills. While, i have taught myself to bs conversations, he hasn't, and it's been difficult for him to date anyone. I mean, he's still a virgin at 28 years of age, so that gives you an idea as to what i'm referring to. I've tried to get him to speak a bit more, but it's a constant struggle. Like i told him, he just needs to go out more. Leave his one bedroom apartment, and meet people. The only way you're going to lose this hermit habit, is by forcing yourself to.
Remember when we took those MBTI Tests and you were confused as to my INTJ. That's pretty much what i am, but i don't come off that way. Just think about that.
With that said, i think you'll be fine dude, just keep your head up.
