Tdap vaccine?

I'm on the fence about the tdap vaccine. I'm not sure if I want to get it at my next appointment when I'll be 35 weeks or if I want to get it when I'm at the hospital after birth. I do plan on giving my baby vaccinations but I not sure if this is something I should do now or wait. Also my doctor hasn't talked to me about it so I don't know if it's worth the risks or not.