Couple of points: FL homestead exemptions are not related to property tax rates. Anyone who owns a house in which she lives (a "homestead") is entitled to a $50,000 exemption, which reduces the assessed value by that amount, then the property taxes are levied on the lower amount. Only the first $25,000 of the standard exemption applies to school taxes. There are additional exemptions for disabled property owners, surviving spouses of first responders killed in the line of duty, and others.
Applying for the exemption (and getting it) does make the home's property taxes subject to the Save Our Homes cap, which means the property taxes can't go up more than 3% a year. I've been in my house for almost 21 years, and I pay several thousands a year less than a person who bought the house today would pay.