Trying to locate old friend (Tina Welch)

Hi,
I have been conducting a (so far fruitless) search for an old friend.
I have searched & searched, & reviewed pay search sites, 99.9% of which are scams( Got that info here!)

I have little info & her name is quite common,not to mention that it has most likely been changed by marriage. I only know her name&her sisters name. She has a brother,but i cannot recall his name. Her mother was divorced when i knew her & i only know the city & state she lived in when we were connected. I say that because we ran into eachother a couple of years later & she told me that she moved to an adjoining state,but i cannot recall the city for sure. That was over 30 years ago. I wanted to reconnect about 25 years ago,but we did not have the power of the internet then & i figured it was an impossible task.

I have tried everything suggested in articles on finding old friends & am pretty much at wits end as far as trying to be "the locator ".
I am now thinking that i would have a better chance if i were post some sort of notice that would be picked up by Tina or one of her friends on search engines.

Something like: "Looking for old friend. Tina Welch from Bowie MD 1975-76 Last known address Arlington? Alexandria? Virginia 1978. Please let me know if you have info on how i can contact her ,or ask her to contact "Ronny" via this post"

I am internet savvy, but have very little experience with the social sites & the proper etiquette for posting a person search.
Near as i can tell my best chance to locate her would be through F B, Twit., or possibly C L.
Maybe someone here knows of a forum for posting people searches?
Any suggestions you have would be greatly appreciated.
Thanks,Ron