I am very confident - if I am doing something I KNOW I can do and IF it is going the way it is supposed to.
Of course, some people are confident when they have NO idea of what they are doing.
Two things - in the classroom - forget confidence. If you have a question ASK it. I have taught groups where EVERYBODY wanted to ask a question and nobody had the guts and I could not straighten thingfs out. If need be, ask after class, go to the office - but get answers. Forget confidence - you NEED to know.
As for family support - I know the feeling. It is not going to happen. I have seen families that tried to stop their daughter doing something she was succeeding at - because they figured she couldn't. I have seen families that had no idea what their son was trying to do.
If you get support, great - but keep walking because it may not happen.