Advice much needed please

Ri`anna • First time mom Baby R👶🏽3/25/19

Soo my friends who have just recently had babies, told me that if I breast feed and thn stop thn my boobs will get saggy. I wanted to combination feed(breast and bottle feed) and I wanted to kno if that would effect thm too. Any advice would be very much appreciated🙌🏾🙌🏾🙌🏾