I was first diagnosed with UC when i was 13 years old.  I remember complaining about it as young as 9 or 10 years old.  I was initially given a 20 mg of prednisone and tapered off by 5 mg a week and i was also put on sulfasalazyne. Well after staying on the sulfasalazyne for about a year i came off and didnt have any problems for about 6 or 7 years.  However when i was about 21 or 22 i got a very bad flare up that hospitilized me for about 2 weeks.  I am now 32 years old and have been having on and off again flare ups.  I think the most ive gone without a flare up now is a year to a year and a half.  I do agree that probiotics can help but i find that taking them (for me) while having a flare up tends to make things worse.  I have tried everything available short of clinical trials.  Right now i am on colazal 750 mg and imuran.  This combination has seemed to have had the most success, but i still get occassional flare ups and have to get on prednisone every so often.  So to answer your question, for me it seemed to go into remission easier  and longer when i was younger.