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.