How to remedy bad sex?

My new boyfriend and I had sex for the first time last night. The foreplay was great, but the actual vaginal penetration was… strange. I felt like he was nervous, and his rhythm was maybe off?

He felt bad and told me its been a while since he’s had sex, but I feel like it was my fault. I told him that practice makes perfect and that we’d just have to keep at it.

Is there anything I should do/say? How can we have better sex?