In general, I ask women requesting elective surgery to wait at least three menstrual periods after childbirth (if NOT breast-feeding), or three menstrual periods after completion of breast-feeding, before undergoing cosmetic surgery (not only of the breasts, but anywhere in the body). This is because there are profound physiologic changes related to the hormonal shifts that occur with pregnancy. These are not trivial.
Since liposuction is elective, and since your body has not returned to its new normal after delivery, why risk a poor result or even a higher risk of complication while your body is still a "moving target?"
Wait for at least 3 months (6 would be better), and concentrate on your baby for now. He or she needs your undivided attention more than you need lipo! Your results will be better as well if your surgeon has a stable-weight, and hormonally-normalized patient to operate on! Best wishes for you and your baby!