If you love writing, and you have some skill in doing so, then definately do it.
It scales well, and it isn't hard. Compared to 2U and 3U English, I found 4U much easier - its just a matter of grabbing hold of inspiration and getting the words on paper so you can refine them. Keeping the journal is by no means a burden.
One factor to consider is whether you will have a helpful teacher, but that is not the definitive word on whether to do it - it just helps if you have a nice, intelligent guide. Our 4U teacher was very dedicated and it made things particularly smooth.
You don't have to be super-organised, so long as you manage your time properly.
If you're good at it, and like it, I would certainly recommend it.