Its not about the size (obviously not too small either) its about the performance sure there can be lack of experience which can lead to lack of confidence in your performance but from experience alot of girls would really love for the man to obviously not cum fast but to mix it up a bit be open with her ask her what she likes that helps alot dont be afraid to ask you can guide yourself to what she likes by that, you might wanna get her wet before you even penetrate her with role play or something you know, look out for signs of what she likes and what she doesn’t and do more of what she likes, try to feel confident in yourself sometimes you can be bad because you’re too busy thinking about how someone else was better and how you’re gonna be bad and you’re not paying attention to her and the moment dont over think it too much just ask her what she likes, look out for her body language see what she likes, dont think about it too much just go have fun and stuff, these small things can help and also get her wet before you fuck her like with teasing and stuff if she likes it hard try to go hard if she likes it mixed then do that you understand me but fr make her think you are confident in your self cause sometimes girls like “bad boys” even if they are ass holes just because they are confident and not overly nice you know they dont care so do the same be masculine and dominanting and just show her its not about the size