My father co-signed on my house with me basically because of my self employment status as a Realtor. I was able to file a homestead no problem. The co-sign does technically make them co-owner and liable for the note just as you are, but it is still considered your primary residence.

If you are not working with a Realtor yet I would love the opportunity to help in any way I can. Whether be helping find a lot or helping negotiate with builders. As an added bonus I rebate you 20% of the commission I make off of the sale.

RJ

If she co-signs she will be a co-owner from what I understand.
You need to check and see if your lender will even allow this.
We've run into some issues lately with co-signers.

You will be able to file for homestead. This is a common loan and is addressed by the homestead rules.
She will indeed be on title though.