Is it normal for me to ask her to do it?

I'm 19 and my girlfriend is 21. We've been together for two years and we've done just about everything (sexually) that couples do now-a-days but there is one thing that I really want her to try and that is, I want her to lick and suck on my balls. Ive heard that when its done right it feels soo good. I haven't asked her to try it yet because I'm wondering if its normal to want to try it and should I shave my balls first. Any thoughts???