I'm trying to learn this part of Free Bird, but I can't seem to finger it right. Most people suggest using the pinky to hit the 18 e note, while using your ring finger for bending the 18 B note, yet for the life of me, I can not fit my finger behind my ring finger! I don't have huge hands either, so I don't know how you all do it. Any advice?

you could use your index and just slide up to the fifteenth when you get there. theres something called a finger roll, basically wut u do is roll the tip of your finger from the lower string to the higher one and fret with the pad of your finger instead of the tip.
for that part of the song i use my third finger to bend the b string and while bending i lay the same finger on the e string and hit that too!