On your first cape you get, you get a plain one, right?

 

And the second cape you get is a trimmed cape, right?

 

Well, if i buy 2 of the same capes, will 1 be trimmed and 1 be not trimmed, and im talking about on my first lvl99 skill.

Nope, you must have two different types of skill cape, then they'll both be trimmed.

So , say i get a the woodcutting first, it will be plan until i get a second cape, then they will both turn trimmed?

Yes, as soon as you hit 99 in the second skill your first skill cape will trim itself automatically, and your second cape will be trimmed when you go buy it.

ah, thats very helpful to know. Thanks a lot!