Well you will get all sorts of advice on this topic mate.
But here is MY two cents:
Get in touch with her properly either by phone or email explaining nothing about religion, and talking only about your freindship.
You must understand that to a Jehovahs Witness, especially a zealous JW who has gone to pioneer school to become a regular pioneer, that friendships are conditional, although they will deny it if you ever did put it to them. (and Dont)
A worldly person is someone to a JW is someone who is friends with the devil and does not know God. Only Jehovahs Witnesses Know God.
its all BS. Jesus dwells in each of us if you would just accept him, although people on this board have much more different perspectives, this is just my personal beilef.
My advice to you friend, is to re establish a connection with her, if she really is a close friend and you really want to be in touch with her, and when you have made your bond again, do not bring up any religious talks on your part or hers.
Tell her you will not tell her about your religion and you would appreciate if she didn't tell you about hers, you just want to remain freinds because she was the closest a friend you ever had and dont want to lose her.
Then slowly, sometime in the future there are subtle ways of dropping hints to her that will stay in her mind and get her thinking. Stick around here long enough to learn from some very wise people in this false faith.
Many of the people here were ex elders 50 years + etc.
I myself only studied for a year, i was a mere indocrtination student, but know enough about it to be destroyed at armageddon.......! lol
Good day
DM6
PS, for the love of God! Do not tell her ANYTHING about you researching online about her religion at this stage, leave that until later. She will drop you so quickly she may think you are the devil himself.