Dear heartbreaken,
From this case, obviously you can see one thing - your definition
of love & relationship is very much different from hers. As a
couple, being together is secondary - looking at the same direction
is primary. If you expect certain improvements (the 6 months
anniversary, etc) or some points from her, do communicate and TELL
her instead of thinking that she will know what you want. Not
everyone couple is imbued with couple's telepathy (known as Xing
ling xiang tong in Mandarin), so don't assume. 
You have been very compromising - to a fault. Its important to
compromise in a relationship, however, do you know feelings must be
exchange and be understood? Whats the use of showing someone how
much you love her, but she don't even realise and appreciate? You
have to tell her all these - not as in how 'great' you are treating
her, but as in to let her know, you do love her and thats why you
all doing all this.
When she score lower marks for her test, in any aspect it totally
crazy to vent her anger on you. You feel hurt everytime she does
that, don't talk to you over small mundane stuff - TELL HER. Next
time before you even question her about her result - ask her if she
needs the time to be alone, if yes, then let her be alone for a
moment in school, with her friends, etc. Anyway, you would be there
for her if she needed you - I believe you will.
The problems lies within you actually. Its not that you want her to
change for your sake , etc - but rather you want her to improve and
make this relationship better. Many a times when guys/girls get too
compromising, this relation start to waver because they themselves
are blind to their own faults.
Cheers
