I gave my mom temporary guardianship of my son so that i could go to school. now i want him back and she?

does not want me to take him. all we did was a notarized doent. she has only had him for 2 months because all i went to school for was to get my ged. he is in school ow so any further education i want to get i can go to while he is at school. can i just take him back if i get a letter notarized ending the temporary guardianship?