I am an introvert, but I am confident. I get told by people who don't even know me write 'There is no way you are an introvert when you show off your body.' They couldn't be more wrong.
I am not outgoing, unless I'm comfortable, and that takes awhile. I enjoy my alone time. I prefer staying at home, instead of going out. I hate talking on the phone, unless I have to, which will be at work. There are times I don't mind chatting online, and then there are times when I don't feel like it, and shut down.
As for confidence, yes I have it. I'm going to be 48 this year , so I think I have earned that right. I just know I am happy being a confident introvert.