send her out on the town she will come back baring gifts
If she's old enough to go into heat, she's old enough to get spayed. See another vet. Many are spayed at 8 weeks. Very few wait until the old idea of 6 months. Getting pregnant too young can be really hard on your kitty.
http://www.aspca.org/pet-care/general-pet-care/spayneuter-your-pet