You can rebuild your stamina. No worries. It will just take time.
Furthermore, not every girl is interested in being pounded for hours on end. Focus on finesse and good foreplay, and those two minutes can be more than enough for the both of you. But yeah, a little more would probably be good
And personally, being told "it's too good" is the compliment of a lifetime
She's cool with it for a reason--you've made her feel like a sex goddess.
And hell, Johnny, you're so hot it wouldn't matter!