Depends also on the company size and ambition that you applied to. Are you still happy flying the ATR or is it time for something else? A320 self sponsoren TR sounds like easyjet. I would seriously consider taking that step. You probably have a few hours on the ATR so you can enter the command proces pretty much straight away. Does the company require lots of upgrades? If its easy then yes for sure. Probably 2-3 years and you have your command on a 320. If the money is kind of the same then its an easy decision. Look at it on the long term.