First time flying and plane seats aren't next to eachother#?

I am 16 years old and my brother is 13, and we've both never flown at all in our lives. My parents are sending us to visit family in Atlanta, Georgia and we live in Columbus, Ohio. We will be flying out of Dayton, Ohio to Charlotte, North Carolina, then take a seperate plane to Atlanta. The thing is, when my parents bought the tickets, they were one of the last ones left, and the seats aren't together. I am freaking out because I've never flown ONCE in my entire life, and neither has my brother. And it's not like my parents are going either, it's just my brother and I going. I wanted to sit with him so we could experience the flight together. I'm also worried about the whole switching planes ordeal. Now that the date of the flight is near (Monday), I'm getting extremely worried. Help! Thanks in advance.