Hi Patricia,
I agree with what Sophea has written.
The co-executors of your mother's estate have a fiduciary duty to act in the interests of the beneficiaries as a whole. Alternatively, if the house is left to a particular beneficiary, then the co-executors must act in the best interests of that beneficiary in relation to the house, but without substantially damaging the interests of other beneficiaries (e.g. in the situation where the estate cannot cover all expenses and costs and all gifts must be apportioned).
As Sophea has mentioned, in order to protect the interests of the beneficiaries, the co-executors can charge whomever is living in the house a reasonable amount of rent in order to maintain/increase the value of the estate. If you wish to continue living in there, you can negotiate to pay this rent or have it set-off against your beneficial share of the house when probate is granted and the estate is administered.