When did you realise that someone has a crush on you?

There's this guy whom I occasionally work with. He's in another building so we usually call or email. I never really considered him anything. But he recently added me on Facebook with the excuse of slforwarding me a voice note recorded by an engineer who was in contact with to fix a certain issue. I mean it qasnreally urgent and he even said befor that he could send him an email. But that same day at night he added me on Facebook and messaged me his voice note and we chatted a little. The next day I asked him if we can have a conference call with the guy, he told me he can only text him so he gave me his number and asked me to send him a voice message to forward it to this engineer. I recently posted a story about my accessories business and he slid ito my DM and we talked about it for like 3 hours and showed me his own men's collection of accessories that he wears, he was so impressed and recommended adding a line for nen. Last Thursday night, we texted again for like an hour about work, then he asked me how long have I been working in this field, so I sent him a long voice.

Now herethe thing, he kinda disappeared and replied late after this last voice message. Mind you, I'm an older woman , 7 years older. I guess he knew that before from my bio on Facebook. I didn't hide that from him but my insecurities are playing in my head that he is pulling away bekcausebof the age gap. I don't know. My friends say that him adding me on Facebook wasn't really about work, because he could have talked to be the next day on the work phone without having to add me. This is just an excuse. But now I feel like he's pulling away. I'm starting to catch feelings even though he was never on my mind before.

What do you guys think?