Im 20yr old, weigh 133lbs and have stretchmarks on my lower abs. What is the best option lipo or a tummy tuck?

I had a baby when I was 17 and didn't gain that much but my tummy has got quite big. I'm so ashamed of it that I hide myself away and wear baggy clothes. As my 21st birthday present my mum has agreed to pay for plastic surgery as she has seen how withdrawn I am. I'm going for a consultation on Thursday for a tummy tuck but don't know if it is the right thing or if liposuction is better. Problem is I have a few stretchmarks on my lower abdomen. I am really scared if the surgery will also go wrong and if anyone has had either of these done with the same cirstances.