As a seller and your FHA mortgage rate is below the current rates, you have a selling advantage. 
As long as your agent has the mortgage experience to understand the loan guidelines and how to market the Net Present Value of the saving of monthly payment from current market rates to your below market rate.   

The buyers are looking to purchase properties, they’ll need to qualify for a new loan. As interest rates rise (like they have been), the actual monthly cost of a mortgage payment increases as well. A house with the same purchase price is immediately more expensive.

If you’re able to advertise that your home comes with a mortgage at a lower interest rate than what is currently available on the market, you’re putting money in the buyer’s pocket without taking any money out of your own. 

If the agent has a financial background and knows how to market  the montly saving to the buyer, you’re giving yourself an immediate edge over your neighbors selling their homes. For example, If two homes are the same price, yet your home costs a buyer $100 less per month due to your lower interest rate, you win. Your house sells while your neighbor’s does not.

There are some downsides for the buyer to consider and must be conveyed.  The buyer will have to have an increased down payment to cover the equity in the house or qualify for a 2nd mortgage which could decrease some of the monthly savings from the 1st position lower rate assumable loan.