I (F23) finally asked a guy (M23) out and got rejected- and my friends are making me feel so embarrassed for it. Was it really such a bad idea

I recently decided to ask out this guy I’ve been friends with for some time while volunteering at a library. Since our volunteering positions are going to end soon, I decided to just be really upfront. I asked him out for coffee and he said yes. We were having a great time, and at one point we started talking about relationships etc. etc. and turns out he is actually seeing someone else at the moment. This made me a little sad since I did really like him and I really enjoy spending time with him as we have a lot in common. Anyways, in the end the guy figured out that I had a crush on him and that’s why I asked him for coffee so I could get to know him- but I said there was no very hot feelings as he still wanted to be friends which I didn’t have a problem with.

So, after that day, I talked to some of my girl friends about what happened- and all of them except one basically told me that I was so dumb for asking a guy out and it looked super desperate. They even said things like are you in grade school? Why would you tell a guy you like him? etc. etc. After hearing all this, I am feeling really embarrassed and kinda lame that I did it even though initially I thought I was being upfront and confident. I mean how would someone know I’m interested in them if I don’t let them know? I’m really shy and introverted myself so I’m not really good at dropping hints and playing very hot to get or whatever. Can someone give me advice on whether it is really that lame or dumb to ask a guy out and being upfront?

Tl;dr: Asked out a guy and got rejected and all my friends think I was desperate and lame to ask a guy out as a woman. Can someone give me advice on whether it is really that lame or dumb to ask a guy out and being upfront?