CX
I would suggest that if you have an opportunity to fly the A320 then take it and make the most of it. Upgrade when the opportunity presents itself. Once you have the requirements for CX, then apply. Make sure you meet the medical standards and also take a prep course prior to the interview. From an airline standpoint, jet time is always looked upon favorably, but most importantly is PIC time. Heavy jet time will also be a plus. If turboprop time is all you can get, then by all means that's ok too. Good luck.