Membrane sweep.

My doctor gave me the option at my next visit to do a membrane sweep. I will be 38wks which will also be my last ultrasound and my frist time having my cervix check. Im a FTM & exactly 37wks and have not been experiencing any contractions. I feel like if I'm to do it I might wait till I'm 39wks to 40wks. My plan is to be induced at 41wks if nothing is to happen. (We have family flying in from NY to CA on my 42wk in hopes that our baby would be here)

Has anyone had a sweep preformed before? 

I've heard there's a 20-30% of going into labor within 48hrs. What was your experience?

Any extra knowledge/insight on this would be greatly appreciated. 

My cervix may not be dialated enough to even have it preformed for all I know.