Cellulite, loose skin, and stretch marks

I'm an 18 year old female - 5'5'' and 176 pounds. Always been on on/off 'diets'. I noticed this huge red stretch mark below my stomach the other day and that freaked me out enough to panic and search for a more sustainable long term way to lose weight. (as opposed to binging, not eating anything for 2 days out of shame, rinse and repeat)

I'm absolutely terrified of being left with loose skin after I'm hopefully at my goal weight (120 pounds) - is there anyway to prevent that? I wanna wear bikinis and crop tops and I guess I'm at an age where that superficial stuff matters to me.

Plus cellulite and cottage cheese skin and stretch marks :( - will they fade away by strength exercises or oil massages? Coffee??? Dry brushing? Do I have to eat anything specific?

I've hated my body for so long and now that I'm finally making steps to change this fear is completely gripping me and pretty much demotivating me. I've been looking for tips but all I've been reading is how people made peace with their loose skin - I don't wanna make peace with it! I don't want it! (I'm aware this comes off as bratty and annoying...sorry)

So yeah. I guess my question is, are there any steps I can take right to now to prevent it?

(I know it's been mentioned in the sidebar, but I guess I'm looking for first hand experience)