Why did my guy friend ask about my breasts and my bra size and why did he keep saying "Kidding hahaha" everytime I told him to move on or forget it?

We were like talking about my vacation that I went to about 5 years ago. Then I was telling him how much of a warm country it is and that I had to wear a vest to sleep to keep cool. I told him that it was about 5 years ago and I was about 11 years old that time and stuff. He was like "Well how was your breasts?". "Did you wear a bra?". "How about your mum?". Like he asked 3 questions at once within a few seconds. He didn't even let me answer the first one before asking another lol... I don't know why he did that, any Ideas why? Anyway after that I was like "I didn't wear a bra that time". Then he was like "Yeah you were 11... Isn't it budding that time?". "Hahaha how about now?". Like again he asked all these questions at the same time without me being able to respond to the first one first. Again I don't know why. Then I was like "Oh please move on". Then he was like "Hahaha kidding". Then I was like "Of course I have boobs now lol". Then he was like "What size? Hahaha". Then I was like "Forger it". Then he was like "Lol Just wondering". "36b?". Then when I took too long to respond he was like "Haha forget it". But yeah he obviously didn't ask out of the blue I think he tried blending it in a bit. But it feels like he's always wanted to ask me my bra size. But I noticed whenever I rode along with the conversation and kept answering his questions he would keep this conversation going, and when I didn't Initiate as much he kept saying he was Just kidding. I don't know why he kept doing that everytime I didn't Initiate or why he asked me bra size...
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He's 25 if you're all wondering...
Why did my guy friend ask about my breasts and my bra size and why did he keep saying "Kidding hahaha" everytime I told him to move on or forget it?
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