Can my siblings legally force me to sell an estate we jointly owned?

If you can't buy out their interest, they do have the right to "partion" or sell their interest in the real estate.

Unfortunately, you don't say who your late mother left the house to. If it was left in her Will directly and solely to you, then, you may not have to sell it unless there are debts that need to be paid for and there is no other source of money with which to pay those debts. If it was left to all siblings, then, regardless of the fact that you're living there and paying the mortgage and expenses, you may have to sell it to settle the claims of the rest of the children. You can't expect to live in the house if all of them were given it together and none of them are living there. Of course, all of this depends upon how the Will reads. I strongly suggest you hire an attorney to sort this all out. Good luck.

None. When there are multiple owners, any owner can force a partition. Your right is to get your fair percentage of the sale.