I was in a similar situation a few years ago.
I never knew my dad, he never paid child support. I grew up with my mom telling me he left knowing about me and that she didn't know where he was. She married my step-dad when I was 7. When his first son got old enough to play baseball my life changed because he became the favorite. Eventually I got tired of the way he treated me and told my mom and counselor I wanted to meet my real dad. Mom said she would start looking, even got the step-dad to say he would help (they were in the same fraternity).
This went on for years. When Facebook became the main social media site I figured it wouldn't hurt to search for him. Sure enough, I found him. One of his pictures was of his son, he looked exactly like I did when I was younger. So I told my mom and sent him a message. It was awkward as fuck sending some random person a message saying "hey, do you know x? I'm pretty sure you're my dad." and I'm sure it was awkward for him, too. Since I was 17 at the time my mom refused to let me see him, constantly reminding me that he left knowing about me and my step-dad even got in on it, saying "You can ask any of the guys in the frat, he knew about you". His story was different, of course, but even he made the same remark about the frat. For the next year or so we kept talking via Facebook, text, calls and I was trying to figure out the truth while getting to know him better.
A year of sitting at home wondering what to do after HS I finally got to meet him. Now, I was just like you. I didn't know anything besides the sound of his voice and his general personality, but I didn't know if it was all a show. I was nervous as hell. It was only for a few days, I was on my way to basic training, but it was probably the best time I'd had in years. It was strange, too, because I felt (and still feel) more at home there, with people I've never met until I was 18, I felt more at home than I had my entire life.
I didn't exactly mean to just blurt my story out, but I figured it was the best way to express how much I understand. I know our father situation is most likely different, but in my opinion if you aren't talking to your biological father at all, talk to him. If things go well, go meet him. If things don't work out at least you can say you tried. If they do, you just gained a best friend. I don't know anything about child support or how it works after the child in question turns 18, but if things don't work out then you can pursue that route if you want.
TL;DR - Talk to your dad if you aren't, then go visit. Might gain a best friend.