When you spend so much time with adults and go through hardships that your friends and classmates can't imagine, you become more mature than your peers. You can no longer relate to the drama, silliness, and immaturity of some middle school and/or high school students. It's like the movie “17 Again”, with Matthew Perry and Zac Efron. You feel like (and really are) an adult stuck in a teenager's body. It can be really challenging trying to figure out how to get along with other teenagers (even though they are your age) after spending so much time around adults and going through something that makes you grow up so quickly.
You may feel, many times, like you hate high school and are just waiting to move on to college, or even beyond that, to start fresh with people who are so much less mature than you have become. As frustrated as you may be, it is so important to find a way to somewhat enjoy the years of school you have left, especially after missing so much. Try to accept the fact that you are going to be far more mature than most of your peers and that feelings of frustration and annoyance are completely normal.
The thing that helped me the most was finding other teens that had survived cancer, or another serious illness. Through similar hardships, they had become equally mature, and were dealing with issues with friends and people their age as well. Try to find a support group or somewhere that teens who have or have had cancer or other serious illnesses can get together. There was no support group just for teens that have or have had cancer in my area, so I started one with 3 of my friends from Camp Sunrise (the camp I go to for children and teens who have or have had cancer). I was pleasantly surprised to find out that some of those girls were also struggling with people at their high schools, and that I was not the only one. When we have issues with people and friends from our schools, we always have each other to turn to as friends, which is very comforting.
If you are going back to school after being in treatment for a while, try treating your return to school as if you are going to another country and learning a new language. This can be helpful because none of your friends and classmates in school will be able to speak your language – trauma, pain, isolation, nausea, hair loss, etc. Don’t expect them to understand, they can’t!! Take it slow. Don’t expect that you will get along with your old friends or that they will understand what you went through. Try to meet new people and make new friends, even if it means finding people in grades above yours or people who don't go to your school.
Being so mature, and sometimes more comfortable around adults than most people your own age, is definitely an inconvenience now. In the future, when it comes to applying to colleges and jobs, however, it will help you get ahead and create a positive future for yourself. In the mean time, create as much of a positive present for yourself as possible and try to enjoy the few teenage years you have left before really becoming an adult.