My mother passed her condo onto me through a quitclaim process before she died. Do I owe any taxes on it?

My late mother passed her condo onto me through a quitclaim process 10 years before she died. I was told by my income tax preparer that she should have paid some kind of a tax. But she never filed income taxes for years as she was not required to because of her low income and was not advised to do so by her estate financial planner who took care of the quitclaim process for her.Also, I live in California as did my mother. I read online that according to state law, should I sell the condo, I would only receive what it was worth at the time of the quitclaim and have to pay taxes on that amount. Is this true? My late mother…