Well, its nice to work on it if the gf is concerned about it, but reality is you are perfectly normal.
Please do not take the review countdowns as gospel. Over 10 years, and I can count on 1 hand the number of guys who really do last more than 10 minutes, fwiw. If someone does, then you know they are manipulating it in some way. (we can always tell the difference between someone who is doing it in a natural way (maybe stress interference) and someone who is doing it in a deliberate way. The guys who do it deliberately in session are NOT popular).
But you wish to have it happen for your personal life. One thing if she is thinking she would like you to last longer I would suggest more foreplay. Set the stage well before penetration, so that time length does not need to be so long, or the orgasm is created outside not inside. There is a really good chance she enjoys intercourse, but will never cum that way. She may feel like she is getting closer, but reality is at least 50 % of women do not cum this way, but a lot of them (and men) don\'t know this and think they are supposed to. I\'ve had encounters well over an hour and never cum with that as the only thing going on, no reason to believe any more time is going to work either.
There may be some toys or accessories you can work with that would combine clitoral stimulation with stamina, something that connects with a cock ring for example. But I\'d suggest rather than blaming you, your GF needs to check herself and figure out if that is even possible for her. Rather than just complain about it, maybe she should be figuring out a way to help.