Having a tummy tuck from extreme weight loss before kids?

Thank you for the question and congratulations on your successful wight loss. Based on your weight loss history, description of concerns, and goals, I think it would be perfectly reasonable to undergo tummy tuck surgery at this point, as long as you understand that additional surgery may (or may not) be necessary subsequent to pregnancies.
Pregnancy after abdominoplasty may cause CHANGES that MAY require further surgery to correct.  Ultimately, especially in situations like yours, timing of tummy tuck surgery will be a very personal decision that can only made after careful consideration of pros and cons associated with each option.   
I hope this, and the attached link (dedicated to abdominal wall contouring surgery concerns) helps.  You will find a separate page, on the same website, dedicated to patients who have experienced significant weight loss.   Best wishes.

Congratulations on your weight loss!  You may want to consider having the excess skin from your lower abdomen removed, called a panniculectomy, versus having a complete tummy tuck.  The result will not be as dramatic as a tummy tuck but should help improve shape.  Visit with a board certified plastic surgeon in your area to learn more.