how long does sex usually last for you? single/taken

im fifteen & my boyfriend is sixteen. my birthday is in a few days & his about 4 months. i find he kind of cums quickly so i told him to hold off as long as he can, we started at 3:23 & ended at 3:53. i guess basically my question is, when you were a teen how long did sex usually last for/ in long term relationships, has your boyfriend developed a tolerance? & is sex just better when you're older