Babysteps09...I'm no expert on dating, internet or otherwise but...pardon the pun?...why don't you take a leaf from your own name? Take the babystep of just accepting this womans offer as JUST a friend who happens to be a woman. What more can she expect on a first "date"? Take the view that most women wanna be friends first...it's impossible to long-term date an enemy LOL!
And as for your mental health problems...she doesn't need to know that straight away! Let her get to know you as a person first and...if you both hit it off, if she's a decent woman...your mental health shouldn't matter to her!
Just take the first baby step, relax and enjoy! Just my opinion as a woman LOL.