Not ready for a relationship but?

So there's this guy.

I like him and he likes me back and it's been like this for about a year now but I've been putting off any sort of relationship because I just feel like I'm not ready.

But I'm worried that he will get fed up with waiting and I'll lose the chance so when he asked me out again I said yes but I'm still really unsure.

I'm about to start year 11 and i don't know if I can deal with a relationship (he's a year younger) because I'm extremely awkward and i don't know how to explain it. I want a relationship and to be with him but at the same time I'm not ready.

I just feel so inexperienced and young.