I really hate to have to burst your bubble. You are already in deep trouble. You may have already gone past the point of no return. That first pen, especially one that is a complete success such as yours is, is all too often the falling off point into "THE ADDICTION!" Your only hope of sving yourself is to immediately pack up all your lathe tools, lathe, blanks and kits, oh yes, and that wonderful pen you posted and send it all to me, postage paid. That way, and only that way, you stand the slimiest chance of being cured of it.
Just kidding. My first pen went the way of so many of my other failures, in the 55 gallon barrel of oops most of us have handy. Yours, on the other hand, is a genuine keeper. To practice the CA finish, grab some trash wood and drill a 1/4" hole in it, square the ends and put it on the mandrel. No tube needed. Turn it and apply some CA. Looks awful? Fine, just turn the finish off and do it again. That way you have not destroyed any good expensive blanks learning how to do the CA finish and you have something to photograph when you need to ask a question about what you did wrong. That makes giving help on the finish much easier. Have fun, make a whole bunch of shavings and be careful. Oh, I almost forgot, if you do not have any type of dust collection, that is an absolute must.
Charles