Me and my girlfriend are 17. We have a one year old son. We both have jobs at the mall of america, mine is lids and her's is aeropastle. Can we rent an apartment if my mom cosigns ?

Depends on what the apartment lease says. Some will accept cosigners some won't. Your income and any credit rating you have will be the primary factor. Some apt's have a minimum age requirement. Check around and see what they say.

I agree, most places will not allow minors to be tenants, even with a non-resident co-signer

You may get an apartment if your mom rents it, in her name, but many places will not rent to 17 year olds, so don't expect it to be really nice.

Also many may also need her parent to sign since she is a minor also.