All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger.
You did not clarify the reason for which your grandmother refused to take her share and whether she gave her consent for selling the house or not. The ruling depends on that information. However, if we assume that she agreed with selling the house and refused to take her share and left it for you, then it should be divided equally among you unless she specified a certain percentage for each of you or gave up her share in favor of one of you apart from the others. In this case, her share would be for that person in particular.
Hence, we need to know the reason for her refusal and whether she has given up her share or not; she should be asked about this first.
Also, please note that the grandmother's share is one-sixth of the estate, if there are no other heirs entitled to inherit other than those mentioned in the question.
Allah knows best.