My husband cycles and is nearly hit often. Sometimes because drivers are just not looking out for cyclists, but other drivers are more cynical. He's had things thrown at him. This even happens when he has the right of way, say turning left at a red light. Drivers just don't want to slow down.
I like the critical mass ride because it lets drivers know that cyclists are out there and they have the same rights as other drivers. It also brings visibility to the need for bike lanes and other cyclist and pedestrian friendly access on public roadways.
Enjoy your new hobby! You get exercise, fresh air and a different perspective on the area. A better choice than sitting in a windowless box for 2 hours on a Sunday morning.