IBS has been mentioned above, and while IBS is no fun at all it is far less severe than IBD (crohns or colitis).
I was first diagnosed with Crohns over 20 years ago, and while I was very very ill for the first few years, I’m in pretty decent shape now, with no major flare ups for several years.
Time is a major thing, as it’s the only way you will learn how food and activity affect it. It can also take a while to find the right drug treatment – taking immunosupressants was the big turning point for me. Day to day, avoiding high residue foods, cooking all my own food from fresh, and cutting out booze seems to keep me well. Also (and this may sound silly, but..) eating slowly and chewing food about a billion times helps a lot. Exercise makes a huge difference, although during any flare ups rest is what is required. At all times, sleep is a good thing. More so now that I have two young children :o/
The main problem now is the initial acute phases have left me with extensive scarring and strictures – only thing that will fix that is surgery. If the disease can be got under control early, then hopefully that can be avoided.
Keep your spirits up – while it is a nasty illness, it can be controlled and managed and there is no reason why your daughter will not be able to live a full and active life. There is plenty of support and help out there too, so you’re not alone.