Younger and Shorter

I had drinks last night with a theater friend, who I will not disclose my age to. I don't really tell anyone in the theater community my age because I feel like they need to know that I'm their stage manager, not that I'm their young stage manager.
We were talking about my age (one of his favorite topics) and I mentioned that a Stinky Cheese cast member had guessed I was 21, which bothered me.
"Why?" He asked. "Most people want to look younger than they are."
"Well, for a lot of reasons. [Insert irrelevant conversation bits here until...] But still: I don't look 21, do I?"
He considers me for a moment and says, "This will sound weird, but you do look younger than you did in the fall. And shorter."
I raise my eyebrows at him.
"Maybe it's because you were my stage manager and telling me what to do, that you seemed taller and older? .... Or because when we talked I was usually sitting down [at his piano] and you were standing up?.... Also, you've worn your hair up the last couple times I've seen you and you didn't do that then."
I know that this is, in no way, the actual reason why I look shorter and younger, but I lamely offer: "Yeah, I couldn't wear it up then. I've been growing it out."
Satisfied, he smiles and says, "That must be it," before moving on to another topic.

The reason why I look younger and shorter to him is because I have lost 30lbs since he first met me; I knew that was the reason as soon as he brought it up. While he spoke, I thought about telling him. I decided I should and then opened my mouth to do so and ended up just taking a sip of whiskey instead.
I am working on telling people. I've had serious conversations about weight loss and food and shame with two friends now, and I made a look-at-me-I'm-super-casual-about-this remark about it in front of two male friends last night, who I assumed already knew from their girlfriends, though Ive never talked to either of them about it specifically. I'm trying to 'fake it till you make' with this, acting like its not a scary thing until it is no longer a scary thing.
But I couldn't tell Chris. Maybe it's because I like him so much and we're just starting out on this whole friendship thing. Maybe it's because I'm ridiculously attracted to him. Maybe it's because he's a guy and I have a harder time opening up to men. Who knows? The point is: I let him believe that I now look younger and shorter than I did in the fall because my hair is longer, which feels pretty stupid right about now.

The bright side of all this is that people are beginning to notice. The downside is that, as they notice, I should probably be honest with them about what they are seeing.