nfa

I have a girlfriend. We've been going out for about two months now.. Things are going pretty good, well, I think..

One problem though.. We haven't had sex yet, which isn't the problem though - just background info - but every time we get together, we make out for a bit, she gives me a handjob or head, I feel her up a bit.. However, the other day, when I asked to return the favour, she pulled back and said no. I got a bit cut and kind of ignored her, and she kept trying to get my attention and cheer me up and stuff, but she wouldn't say why she wouldn't let me do anything to her.

Is this normal, or should I suspect something more? I'm new to all this so I don't really know.. Can anyone help?

Cheers for assistance
nfa