Dear LKR,

Most schools do not specify a time requirement, but since this school does, I think you should follow it. When a school explicitly gives a direction and you do not follow it, the admissions people will view that negatively and might even conclude you have poor judgment. I understand that your TFA experience is probably the best example, so you might contact the admission office and inquire as to how strict they are on the "3 year" guideline. They might tell you not to worry about it, but they might say it is very important. Better to know the answer than make an assumption.

Good luck,
Lisa