HATE thighs.. stretch marks, cellulite at only 17?

im really pale so it doesnt help.. & im not fake tanning. idk how the strtch marks got there could it be from bad diet... i havent gained or lost weight.. ive pretty muh been this size for like 3 years atleast i think? i weigh 140 i excersize walk a lot still doesnt help ive tried bio oil hate it i feel really uncomfortable about the lower half of my body in a swimsuit...