Well it's really up to you if want to try for another one. Honestly though, even if you don't have a second girl, she has 2 brothers whom she can bond well with. I get along with my brother well and we are close. The relationship may be different from a "sisterly" relationship, but it's really something your DD is lucky to have and is something to treasure. Try not to forget that. However you are right that there is no guarantee, it is all on how you rear them.

Proud auntie to..
P born November 18, 2000
E born May 30, 2003
D born December 1, 2004
N born September 5, 2006
M born June 3, 2008
D born June 27, 2008
Y born July 19, 2008
G born November 2, 2009
C born November 26, 2010

E & F born October 9, 2011
A born October 24, 2011
D born September 5, 2012
-newest of em all-S born November 11, 2012