Vitamin c and retinol do reduce signs of ageing . The age start using them depends much on lifestyle. 30-40 is a good time for using them , however they should used under guidance only specially retinol . Contact online / visit a plastic surgeon to find what is suitable for u
Next Steps
This article should help u
https://essencecosmeticsurgery.com/2020/02/22/skin-care-overview/