Glad you joined the site ArianaK!
I've had crohn's and other issues for 14 years, usually a combination of medication and diet is best, rather then just using the medication alone.
I realize you are 15 years old and may not be used to making many of your own meals but I'll tell you what I do anyways and maybe your parents can help you with some of this too.
My advice for diet would be avoid red meat because it is more inflammatory, and eat more chicken breast, turkey and fish which supplies omega 3 fat like dha which can lower inflammation slightly. Reduce your intake of refined sugar like white/cane sugar and corn syrup(in soda) as much as possible. If you want something sweet, eat fruit like organic apples or raisins apples contain soluble fiber which can feed the good microbes in your intestine. Consider replacing milk with another dairy product for calcium, like yogurt. Increasing monounsaturated fats is also a good idea, canola oil is good, and nuts and seeds are also good in my experience pistachios in the shell and walnuts are all I can tolerate because they are soft, natural peanut butter is ok sometimes cashews are ok if i chew them real good. Supposedly its the oleic acid that might help lower inflammation LINK
It might also help to know about books like breaking the vicious cycle LINK
which introduces concepts like the Specific Carbohydrate Diet. I've used some of the concepts in the book on my own diet and i find it's true for the most part and can help. This diet advises to limit the types of carbohydrates in your diet to reduce ibd symptoms, simple sugars is one of them also foods that contain certain starches that are in potatoes corn and rice. The book also says to avoid grains but I haven't had any issues with oats or wheat. It also says to make your own yogurt which i find is difficult so I don't do it.
One easy meal I make is whole wheat pasta (barilla) and tomato sauce with canola oil. Find a canned organic tomato sauce and add a clove of garlic, basil or oregano, remove the garlic clove when done and add the sauce to cooked noodles then add canola oil. I make my own sauce from Roma tomatoes but ill skip that for now, that's very time consuming.
I make oatmeal everyday with rolled oats, it's a little time consuming but not difficult. Maybe there is a oat based cereal you could find that's easier to make though. The soluble fiber in oats is really good for our intestine the good bacteria make short chain fatty acids out of them.
In my experience, garlic, onions, celery are vegetables that I cant tolerate at all, but i can add garlic to tomato sauce and remove it after its cooked so I can get the flavor without the fibers. The best veggies in my experience are broccoli
(vitamin a), green peppers, brussells sprouts, kale(vitamin a) and all should be well cooked.
Avoid food with too many additives like artificial sweeteners, or emulsifiers like carageenan, modified cellulose or starch, polysorbate, xanthan gum, and many others. Many supplements have these additives too which is why I make my own. Scientist suspect diets with lots of additive increase the risk of developing ibd and other illness LINK
Making your own green tea could help too, that's pretty easy to do. Better to drink it plain but sweetening with honey might be ok it's not as bad as refined sugars but still keep the honey to a minimum.
Modifying your diet and cooking your own food will be difficult so give yourself time to find ways to achieve these goals. I wish i had more easy solutions to follow the diet.
Eat organic when possible.
Supplements that I use are vitamin d 2000 IU. I also buy now brand calcium, magnesium LINK
, now brand vitamin c in powder form and put them into empty gelatin caps with a small cheap encapsulation device its about 20.00 from the health food store or online LINK
I also take a multi-mineral and a b multi vitamin, both are thorne brand and I also put those into gelatin capsules because most vitamins use materials for their capsules that are synthetic emulsifiers which sometimes feed bad bacteria in the gut. I also take now lycopene and carotenall supplements which also supply vitamin A and other carotenoid which can lower inflammation. I also put these into gelatin capsules.
I might have a few more tips, but this is the majority of what I can think of today, I hope it helps!!