It's Dutch :
ik : I
ben : am
trots : proud
op : of
je : you or your
srry : sms language = sorry : in Dutch we use the same word
moest : had to / I had to
ff : sms language = 'even' in Dutch = 'just' in English
"srry moest ff" : I interpret this as :
"sorry, I just had to say this"
But the big secret in this sentence is 'jumb'.
It looks English to me, but it's not a common word
like the English 'sorry' in the Dutch language.
You sure the spelling is correct?
Edit #1 :
I discovered something and I'm hoping to get an answer
from someone about the word 'jumb'...
I'll let you hear as soon as I got it.
Edit #2 :
I didn't get any answer so far from Amy-Loves-Fashion,
but one part of Amy's message :
voor judith! perfecte perfecte! ik ben trots op je jumb,
srry moest ff .Cool set.
is addressed to Judith-Fashionqueen.
Amy is glad for Judith (one of Amy's favorites, just like you)
that you made this set for her,
and she thinks this set of yours is cool.
Amy calls Judith 'jumb'.
Now I think that 'jumb' means 'jumbo' in the sense of
'super', 'genius', 'wizard'.
So the translation would be, I think :
(This has been made) for Judith! Perfect, perfect!
I'm proud of you, giant.
And this part is addressed to you
(and to other members of Polyvore) :
Sorry, I just had to say this. Cool set.
Hope this helps and good luck!
How do I know? Just Googled, and I'm Dutch.