Should I tell him that I like him?

He (30 yo) is a scorpio like me (21 yo) and there is a problem. We both were formal at first because we didn't know each other well. But we got closer and closer. He was amazing at communicating with me yesterday, like flirting, complimenting and texting me all day. But today he's not talkative and just left me on seen. What should I do? Should I admit my affection?
Should I tell him that I like him?
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