Lots of people struggle with standing up and talking or being in front of a group of people. Just remember that you are probably talking to a group of people that tend to have the same challenge you are having.

One of the ways you can practice is reading to small children as children are not so opinionated and just love the attention. Sometimes that can take place in a local library.
It's OK if you are not perfect. If your face gets a bit red, well, it's got color and that can actually look good from a distance rather than a pale face.