Why is "her house" titled in your name? When did you become owner of "her house"?
But why would you want her to have the sort of low-quality nursing home care that Medicare/Medicaid covers?
First of all, what do you mean when you say that you want to create a trust "for her"? If she would be the trustee and not a beneficiary, then the trust would not be "for her"? Second, why on Earth would you create a trust with a 90 year old as the trustee? Third, you cannot do this without her agreeing. Is she in agreement about this? Fourth, what would make you think she might come to own new properties in the future?
You certainly could do that, and I'll ignore the morbid nature of the possibility of knowing how far in advance of her date of death you're doing things, but, when you refer to "her Living Trust," are you referring to the trust of which she would be the trustee and your siblings would be beneficiaries (and you, presumably would be the trustor/settlor)?
You can transfer property you own to anyone you want.
Huh? If you transfer the property to the trust you described, of which you would not be either trustee or a beneficiary, then that's that. Why would you think it might "go back to [your] estate" (keeping in mind that your estate is something that won't exist until you die)?
I have no real idea how you conceived of this scheme, but I strongly suggest you seek advice from a local estate planning attorney.