Should I do the IUI, or wait longer?? please help?

hello, I am 25 years of old I was on the depo shot for 3 years on and off, i got off of it a year and 5 months ago and i still can't get pregnant, me and my husband thinking to do the IUI- Intrauterine insemination, do you think i should wait longer or any suggestion, please help, thank you.