jeans!!

hi i’m 5’1 and 120 lbs and i need help finding a good pair of jeans that actually fit me (i shop at old navy for jeans). i normally wear a size 12 girls but since my legs have been getting longer, i’ve switched to a 14 kids. now my problem is that the 12’s fit perfectly but they are too short on my legs but the 14’s are way too loose at the waist. i tried a 0 and a 00 and those were still too big so my question is this, where can i find relatively cheaper jeans for girls with long legs and a thinner build?