Should I Join The Swim Team?

i recently changed my next years schedule to the swim team for next year at clements high school. We have 4 teams: freshmen, sopre, junior varsity, varisty. I am currently a freshmen. I am an below avg/averae swimmer. I am planning to practice in my pool and learn to backstroke, troke, flip turn and dive. But, I won't be able to join any team or clinic over the summer cause I won't be in the states in the summer. I am not sure if I will make it into the team, and I do not want to make a fool of myself. Should I go tell the coach I do not want to do it or should I try? There are 4 teams, so would I make it probably or not? I also go to Clements High School in Sugar Land, Texas which is in Fort Bend ISD. Please answer my questions and tell me if its easy to make it into the sopre team.