I need help.

[Shell]

Well since precum contains sperm you should be worried. As soon as you become aroused you're technically leaking sperm and if you shove you unrubbered dick into a vagina she could get pregnant. Its not as bad as cumming in her but you still have the possibility of getting her pregnant. You need to use a condom.
After a few weeks go but a pregnancy test and have her take it twice in two days and go from there.

Also You bloody 15! Why are you having sex?
You last for 6 minutes? I have sex twice and its likely going to take two to three hours.

He was 16 so thats just a tad better, the girl was 15 tho.