Do it now
It is easy to apply for J-1 waiver and then exchange for H1b. Please see what I did in the past 3 years:
1) exchanged my public affair passport for private one;
2) J-1 waiver;
3) NIW-EB2 (DIY)
4) I am applying for H1B exchange
He he, it was hard but we can make it, right? Just do it ASSP. You will always have bread.
Good luck!