I was put on humira around 3 years ago and when I had my first loading dose of four shots, I came back home and I couldn't believe how amazing I felt! I didn't even know how absolutely awful I'd been feeling, until I felt well again. I was pretty concerned about the side effects and I absolutely hate the idea of taking medication, I'm a hippy dippy who likes natural cures and all that. So anyway, last year I decided to stop taking it because I was afraid of the side effects and within a few months my inflammation was as high as when I was first diagnosed (over 100) I was off sick from work and stuck in bed feeling ridiculously depressed (alongside all the nasty effects we all know from Crohn's). Safe to say, the amount of health issues I would have from my Crohn's being active (alongside feeling depressed and being stuck in bed when I'm only in my 20s) was far worse than taking my chances with humira. At least with humira I'm healthy for now, I'm living my life, and if any side effects do occur in the future....then I will deal with that when (or if) it comes to it.
Sorry, I've rambled on. My point is, the awful symptoms of active Crohn's disease are a good enough reason to take your chances with humira. Look after yourself, and be happy. Anything could happen to anybody in the future, so I say take the risk and live your life now.