I think you end up just clicking with a college towards the end, maybe because of the way it looks, how big or small it is etc.
I was very certain on applying to a particular one this time last year, but ended up going for a completely different one once I came to applying.
Read about each of the colleges, see which one you like the feel of. I didn't go for the big reputable ones because, ngl, despite being impressive, their architecture completely put me off. They just looked way too intimidating and like environments of really high pressure. Literally look at their photos and observe your feelings towards them lol.