Hmm. I don't think giving your mom your account login was wrong per-say, but they say you shouldn't care accounts. However, family members are family members.
In future, I would probably advise that you just give her your OW number, and ask her to purchase tokens through paypal - $1 per token, and create a note to state which OW # the tokens are to be applied to - It's the same as buying goodies for others through paypal
Just make the note title something like "See inside for more info." or something