My honest opinion I would go with what you think is best.
I'm currently working on a dio story that started out going in one direction, but now has gone a different route. Think of it as rewritting a script for a movie. You start off with one idea then in turns into something different. If you go with the one year later idea use "flash backs" to fill in what may have been miss. Another idea and I use this alot (God bless my wife and kids for putting up with this) I have them read the rough draft and get their opinion and suggestions. It's amazing some of the ideas they come up with. In either case I hope this helps and good luck.