First of all, did you checked if username Dertai is free?
Probably not all your current watcher would follow your new account. Reposting artwork is hell of work, unless you want to leave it behind.
I would say it's not worth the effort. Many peps have usernames different than names they use everyday.

yeah i have the name actually, its another account i had to spare cx... hmm you're probably tight ;;

In the long run it probably be better to move if you really want to and if you want it to be your main for people to remember. But most watchers probably won't follow over right away and you'll likely lose some, and I can imagine it be a pain to repost stuff D:
You'd just have to let people know like with a link on your page and a submission