It’s tough to say. The vaginal opening will always look small when “resting” (or when nothing is inserted). It stretches to accommodate what is inserted. So I wouldn’t base your concerns on appearance alone. If you’ve had sex multiple times, I would guess that a small opening (or lots of hymen tissue) is no longer a concern because it should have stretched and torn already as needed. My guess would be that you are tense (because each previous experience has been painful, so you may be expecting the worst again) and/or your vagina is a bit on the drier side (again, if you’re nervous and not aroused sufficiently, natural moisture will be lacking). My advice for the next time would be to clear your mind, relax, enjoy the moment with lots of foreplay and use lube.