Looks like I had green coolant in there but my local auto store only had:
Prestone® MAX European Vehicles (Blue) Antifreeze + Coolant
Am I screwed? Should I drain it ASAP?
Edit: the large tank was basically empty so I doubt any mixed yet but there was still some in the smaller tank
Color is not a reliable characteristic for determining coolant. Call the dealer and ask. My car uses G48. That means G48. Not red, blue, green, yellow. G48.