Not in IT but I work in vet medicine. Went into it thinking I’d just work with animals but had to talk to clients more and more as I got promoted. Was nervous as hell first, but with practice I got better and now I’m a hospital manager. My best advice is to just know your stuff really well and at least you’re not stammering to find words and stuttering as well. It might be helpful to have a script and work out different scenarios in your head. It’ll suck at first but promise it’ll get better with time!