Writing about a third year.

I applied to university last year and withdrew everything last minute because of reasons.

I did fairly badly in my exams because of said reasons and decided to do a third year at college to re-do 2 of my A2s and take up a BTEC certificate course.

I’m applying again this year and plan on using the same personal statement with a few changes. The main change, of course, would be writing about my third year and how it affected things.

I really just don’t know where to start. I don’t know how to write about it without it sounding like a bad thing. I don’t know how to make it look like a positive choice I made with positive outcomes.

tl;dr how can I write about a repeated year at college AND make it sound like a good thing?