Can topical Tretinoin/Retin-A stunt my growth?

Hi!  Topical tretinoin is negligible when looking at systemic absorption, so you do not need to worry about growth being stunted.  
I hope you love your treatment! Good luck! 
If at any point you're not satisfied with your treatment, be sure to see a board certified Dermatologist--there is a lot we can do to prevent scarring, blackheads and whiteheads! 

Retinoids do not affect your growth. I wonder if someone said this because they are not recommended in pregnancy, and Accutane, a completely different and much stronger oral Vitamin A derivative, can cause fetal deformities if taken in pregnancy. The worst you could expect would be dry or pink skin from retinols or Retin-A.