Just my opinion and not knowing your experience with 3D printers I would stick with PLA to teach your son and get knowledgeable about it to make sure it prints good.
Move on to PETG which takes a little higher temp like 250 nozzle / 80 build plate
You’ll also need some glue material on the bed for PETG as a release agent otherwise it will stick too much…
If you are using a slicer such as Creality Print 5+ the profiles should be in there for temps and build plate.