First time????!!

So does anyone remember their first time and how it felt? I just had sex for the first time/first few times now and when it was happening it didn't hurt (especially it didn't hurt during the first time) but I sorta felt pressure, maybe like on my bladder or pressure up on my urethra or something (I wish I knew how to explain it better) I pee before sex like you should but was wondering if this was something because I was getting used to it and the way I feel will change over time or it's something bad or serious???? I also don't know if all im feeling is because I TRY to be relaxed and for the most part I am but there's still some part of me that freaks out a little bit. (Which I hope I'll get better with as time goes on.)