I can still run across a road at 30w!! I did it yesterday, and was fine - just a few BH's afterwards, but they are good for your uterus But then I was playing and umpiring netball up to 20w, so its a bit different for me.
Its all about what you are used to, as the others have said, find a specialist instructor and you will be fine.

Some days you will have good days, and others things will be a bit sorer. Its really important not to push yourself on the days you are sore, go away and come back to it another time.