You're living the two sides of the privacy issues created by a world that struggles to dissociate genital configurations when it thinks about 'gender': declare or stealth.
If this person you've met has the kind of empathy faculty that sets them apart from the mainstream world, they'll already have smelt you out, and you'll have 'leaked' in ways that you've not realised (70% of communication is non verbal). And if they have that kind of empathy, they'll know that it's society's limits that make your stealth
acceptable and forgivable and they'll be sad that you needed to hide at all, or in any way, and appreciate that your beauty, sexiness to them, and bodily form are a package.
I do not know what the quality of this person you describe is, how well they've discerned what you're hiding, and what they felt from the prosthesis (hopefully--it felt somewhat different to them--).
I also read 'haven't had bottom surgery yet'.
May I now, change track: I'll share my wisdom by how I tackle this same situation, though I am a gay male, who lost his genitals in a tragedy, and, like you have not had bottom surgery 'yet'.
I spell my situation out from the beginning, because I don't want people in my life who can't extend their empathy faculty to find compassion for what I don't have. I also use humour as I take ownership of the loss and make that a winner. Believe me, I'm beating them off with sticks ATM (for future dating--I disclose up front and refuse coitus atm, and take ownership by saying "
no! Not yet, you'll have to wait" - there's something that makes a lotta lovers very excited knowing they getta guy who can perform, and perform..

"I
will be able to perform as long as you need, and I
will have a bionic phallus. You'll never have to worry that I'll need to go too long or too short. You'll get a lover who will be matched to your cycle. You'll get someone who knows how to make lovemaking more about you than anyone you've known before."
You know, as a guy who had a phallus and lost it - ya know what - I don't miss the darned thing that much. Never did what it was told. Darned thing was a nuisance. I'm looking forwards to my bionic replacement--I really am. I will be able to concentrate on the building of a real sexual connection with a partner, without having to worry about erectile *bleeping* function. So much about having a phallus for a man is about shame and performance anxiety. I swear to god man, the number of times I wanted to perform when I've been with someone really sexy and just was not able to--not enough sleep/anxiety/stressed/yada yada yada!
Suggestion: when you disclose - be in two places at once. Here and now - and in the future - when you're going to be a star, perpetual performing man.
Kind Regards - if you're rejected for the stealth - remember! As my cousin said to me in Athens about dating
"Never run to catch a bus--there's always another one on the way!"