is it safe to use my moms credit card

It is safe if we are talking about trusting Microsoft with the C.C information. But only.....and i will repeat....ONLY if she gives you permission.

Its safe so long as your mum knows youre using it!

That depends, did you ask her to use it first....if not your life may have an unfortunate event.

All forms of payment are safe, to include credit and debit cards on the playstore. I have had my debit card on file for years and never once ever have an issue.

She can even set security up to prevent accidental purchases from you or other players.

Well, you should get your moms permission first, just saying.

Make sure you have her permission!