Welcome to our family. I am sorry that you are dealing with these two diseases at such a young age. We cannot tell you if your illnesses will negatively affect your school. Lupus affects each of us differently; so we have stressors that are individual to us and we have precursors to flare ups that are individual to us. The only advice that I can give you is to take very good care of yourself! Read the "stickys" at the top of each forum, they are filled with great advice and helpful information. They may answer some of your questions. Also, please visit The Lupus Foundation's website as it is also filled with great information.
It is important that you make lifestyle changes that help you to avoid flare-ups (such as avoiding sun exposure and/or fluorescent lighting, avoid stress, avoid infections people and/or situations, get appropriate rest when you can, but also get regular exercise, and eat healthy).
Please know that we are here to help you in any way that we can. I am so glad that you found us and I hope that we are able to be of help to you.
Peace and Blessings
Look For The Good and Praise It!