I started undergrad in nursing and after the first year, realized it wasn't for me. Decided to pursue OT immediately, but also decided to stay at the same school that didn't offer it. Thought it would be easy to get into a program and wound up getting in this year after applying twice.
So I guess the regret comes down to not transferring to a school that had the 3+2 program. A friend of mine did that and while she is finishing her degree this summer, I will only be starting mine.