ok we are both 15 and we met for the first time today. I wanted to meet him/he wanted to meet me for a couple of weeks. We've both been teased by friends for a while saying we will fall deeply in love LOL. But anyway we didnt really talk just said hey. So there was me, my bestfriend, her sister and this boys sister. Then the two brothers, 6 in total. We played grounders on the playground. I fell a few times and i laughed while he also laughed. We only said hey the whole time. When I was looking the other way I caught either him or his bro pointing at me. And I felt like they were talking about me. His sister went & talked to him and came back saying"My brother said 'I thought she didnt have glasses' and i said well she never wears them so i didnt know."

I feel like he was nervous but kind of ignorantly judging me at the same time. I mean we had fun and laughed but I took it as if he was shocked about me being nothing like he imagined.

Sooo I really dont know what to think now.. what does this all add up to & should I try to hang out again this week with them? Thanks for every answer, and Im not interested in any"Your too young" answers. =)

Don't worry, you're not too young. It's not bad to start dating in your mid teens. A lot of guys are shy or awkward upon first meet, you just have to warm up to each other.
&Yeah, ask him to hang out again, but this time I'd suggest not such a big group of people & not siblings. If I were you i'd get one of my friends, him and one of his friends to just hangout. Typically it works good, conversations flow and you guys begin finding common interests. But like you said, the only words exchanged were 'hey', in that case. . . if he's to shy to spark conversation with you, you have to make a conversation with him!
&most people before meeting another will think up an image in their head of what that person will look like, that's probably just what he did. It doesn't mean good or bad, it just means it wasn't what he was expecting. Just keep hanging out & try to warm up to each other.
But just keep in mind, he's not the only guy out there. You'll come across so many others