new to sex

Kassidy
I just recently lost my virginity and I'm new to this whole sex thing. I've slept with this guy roughly 6 times now and 2 out of the 6 times I haven't been able to orgasm. I last much longer than he does but oral sex doesn't do anything for me. The other 4 times I was able to orgasm 2 to 3 times in one go. Is there an explanation for this?