How long should I wait to have a tummy tuck afterc section and what do u tjthink about tummy tucks (witch hazel)?

It depends. I perform a significant number of tummy tucks (witch hazel) each year for my young mothers and feel that this is a great procedure when done by a qualified plastic surgeon with experience in this area. I generally recommend waiting a few months following a c-section so that soft tissue swelling has gone done and your hormones have returned to a more natural state.
At least one. Year. It is a good operation for certain conditions, but not for others. It is best to get opinion from plastic surgeon. It will not treat obesity.
At least 6 months... Great operation for the right patient; the “ideal” patient for tummy tuck surgery is one who has completed pregnancies, is medically/psycho socially/emotionally/financially stable,  has an excellent social support system surrounding him/her,  does not smoke, is capable of arranging enough recovery time and who has reached a long-term stable weight. Best wishes.  .
Wait until older. Before resorting to surgery, see if exercises will achieve a similar result, particularly at your age. As you get older, exercise may not be as effective and if it really bothers you, in the hands of a good surgeon, it's fine.