This hobby is a journey, so I can't say I'd do anything different. Started in HO at 7. Stuck with it until I was 33. Dabbled in N during the late 80's and early 90's. Went to hi-rail O and 3rs between 2002 and 2010, and now mainly focus on 2 rail O for my transition era, while keeping 3R trains to run at my club.
Can't say I have any regrets over it. I learned along the road. The process of discovery is very enjoyable. Is there a coincidence that I have many of the same models of the same roads in N, HO and O? Nope.