Wow. This poem has such an impact with not so many words. The moral is very true. Your point gets clearly across, and the use of the "princess" not only brings good imagery but makes your poem reach all of us girls (even I dreamed of living in a castle, and I'm more of a tomboy).

They dream of living in castles,
with a happily ever after.
Sometimes happily ever after,
is just a dream away.

Hello Hsarver here to review your poem today. I really liked the idea of taking something as cliche as prince charming and turning into something unique, and something that really sends a message. I will start with the positives and then with the things I would change. To start, I love how you opened and ended it in the same way, I thought that was a really good addition to the poem. Also, I would say my favorite stanza would be the fifth one. It is really well put, basically saying yes, it is okay to dream, but understand that you are a princess already, and need no one or no thing to make you that way. Now on to what I would change. The only thing I would add is add a the and many of *right here*girls hold them. Other than that great job on the poem. Keep writing!

This is definitely the sort of poem that I could imagine on the inside cover on a Disney Fairytales book or something similar. It's got some nice imagery, and the message is lovely and uplifting. That being said, it's got several problems.
The first and most glaring weakness is, paradoxically, its greatest strength. Plainly speaking, it's just too formulaic. Pictures of girls wistfully longing to be princesses and live in castles while gazing into mirrors encrusted with plastic jewels is familiar to anyone who grew up in America during the past twenty-or-so-years. This makes for a cute sort of poem, but it also means that there's virtually nothing new here. There's a reason that variety is referred to as "the spice of life," and it has nothing to do with herbs. After a certain point, you *have* to do something different with creative works, or it turns into something that no one will really notice.
The second problem is that, unifying theme aside, the poem doesn't have much flow to it. This is fairly easy to pick up if you're reading aloud, but if you're simply writing it down or typing it (I've noticed that this is a lot easier to miss if you're typing) the lack of rhythm can fly right over your head. In prose, this wouldn't be as much of a problem, but when you're writing poetry, rhythm is of the essence. Especially owing to the fact that this is a non-rhyming poem, this is a fairly glaring flaw that's present throughout the poem.
Beyond that, your writing is, for the most part, grammatically solid.
My suggestion is to either (a) come up with a more original theme for the poem, or (b) make it near-flawlessly exceptional, because when you've picked a theme like this, you have to be careful so as to not sound like you're quoting a popular novel of Frances Hodgson Burnett's.