I am 33 in usa and have a mild sub coronal distal hypospadias that for was not repaired when i was a babe. could this cause problems for me later?

You should be fine: In my practice, I have seen dozens of this type defect and most men have normal excellent sex and have no trouble fathering children.

Problem is unlikely: Should not be problem unless penis is significantly curved (chordee). There is mild risk of urethritis following unprotected sex as vaginal mucus can enter hypospadias urethral opening (meatus) if enlarged. Thus advice to urinate after unprotected sex. This is also good advice for women to reduce risk of urinary infection after intercourse