I had a baby six months ago via iui and i am 38 years old. i want to try again but how long should i wait?

Depends...: This is a question you need to discuss with your gynecologist. If everything is perfect, in general they recomend a year between delivering one baby and getting pregnant with the next as a minimum; that said, at your age, there are a lot of factors to consider, including what problems you've had in the past and the increasing risks of pregnancy as you age.

Depends: If you had a c-section it is best to wait one year. You should have stopped breast feeding for at least one cycle. You should make sure you are not anemic. Because egg quality declines more quickly over 35 i would recommend having an FSH level on day 3 of your next cycle or an amh level to check your ovarian reserve. If this shows reduced reserve then consider trying asap.