Hi, and welcome!
Just to clarify a bit, Minor1 is for characters under 14, and Minor2 covers characters from 14 to 18. Once the character reaches 18, they are considered adult.
The only time we have an issue with a character who is Minor1 or Minor2 is where Real Person Fiction is concerned, We do NOT allow RPF for any person under the age of 18. However, it sounds to me like your story will be an Original Fiction.
The only other thing I would point out is that we do have a specific format for disclaimers for Original Fiction that differs from what we ask for fanfictions. You can read the disclaimer FAQ here, and examples are provided.
Once again, welcome to AFF!