Advice please!

So the IT guy at my job has a big crush on me, I’m starting to like him as well. He’s tried to engage in conversation with me but I get really awkward and shy so he seems to think like I’m not interested and has been talking to me less because of that.

Im very uncomfortable talking to him at work because im very shy and barely communicate collègues. However, I’ve been thinking of asking him to borrow his phone and just add my number to his contact list and give him the chance to text me.

Is this a bad idea?