Hi,
Frozen/ Thawed prey is fine for your snake if it will eat it - I have never used anything else in the last 20 years.
Heating the head of it once defrosted is important so your plan should work. Though it may take several attempts for her to agree with you.
At her size I would say she is capable of eating a small rat so you can also try her on those - though you can get F/T ASF's as well from some companies.
dr del