saluete omnes!
Many elementary Latin grammar manuals will tell you that 'word order does not matter'. This is an oversimplification, mainly aimed at English-speaking students, for whom the idea of inflected endings determining sense is alien.
In fact, Latin word-order indicates subtle variations of emphasis. As a rough and ready guide, look at the first and last words of a sentence to determine the flavour. That said, there's nothing wrong at all with...
Mala quae misit mihi frater meus acerbissima sunt.
...the tone of which is fairly neutral.
But 'mala quae misit...sunt acerbissima!' would throw the weight firmly onto
acerbissima, as would 'acerbissima sunt mala quae misit...'.
I take it you are studying Latin. May I/we know which textbook you are working with and from?
Σ