No, you won't be the first person to do that (post a facebook name, not be sideways!) - it'd be better if you just post your facebook name rather than a link, though, as links in posts tend to attract netbots and suchlike unwanted attention. This way, only people who actually read your post and see you're posting your facebook name will know to look for you there.
I also suggest you specify clearly whether you're out as trans on facebook, and make sure those who get in touch with you this way let you know whether they're out on facebook too, as it's very easy for word to get out when people don't want it to - facebook is pretty public unless you're very strict with your privacy settings (and people are gossips!). I'm not trying to put you off doing it, just that there have been a few mentions of people getting outed by accident this way, so treat it with care

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