When I have sex im done in 3 minutes. I cum out soon. Is it a problem for making my wife pregnant???

That will not. be a problem to get pregnant. First try during the fertility cycle, if unsuccessful you both need to consult fertility specialist , first order will be your sperm count and its motility Good Luck.
Not at all. Thid will not prevent you from becoming a father. You can probably last longer if you put a dan on anesthetic on your glans, try a small dose of an ssri if your physician concurs, or practice the squeeze technique-- read up on it.