I need to gain weight, should I join a weight training cl as an elective?

Right now I'm a junior in Highschool, I weigh about 112 pounds and I am 5 foot 9 inches. I want to bulk and gain weight and muscle, and there is a community college that we can partake in cles for dual credit. One of the cles happens to be a weight training cl, which is tuesdays and thursdays at night, do you think I should take this cl? Also, would it be embaring because I am the weakest( can only lift around 70 pounds) and I am in a junior in highschool that would be taking that class with other highschool dual creditors, and community college students. This would mean i would have no lifting partner, because I know everyone can lift more than that, and it would be even more embarassing if i had to lift with a girl? Anyhow, I need to "get big" somehow, so do you think I should take part in the Weight Training Class? At school, I don't do any sports, and at home and out of school, I don't work out.