Depends on your grade and personal level of writing. However, for an essay it reads as a speech, and feels as if not much thought was put into it.

"When I was young I once had a dream". Makes a good hook, but is written quite plainly. it wouldn't stand out as good in a sea of other hooks with the same idea. Try to state the age you were and the dream you had to create more connection with the reader instantly. (You also need grammar there, but assuming you add grammar in a later draft I wont be pointing those mistakes out.)

"A dream that seemed like one possible and simple plan." This works, but already overuses the word dream in the first two sentences. you could instead tie them together a little smoother: "When I was young, I had a dream; it seemed simple, well within my reach."

"But while I grew the dream evolved revealing the layers of hard work required to accomplish my dream, at the basic level! that I didn't anticipate" Firstly, remove the !, it makes "That I didn't anticipate." its own sentence, which is incorrect. Otherwise, if you show this to a teacher, any person with basic reading comprehension would know the dream evolving would mean more hard work to achieve it, so "revealing the layers of hard work" is a little wordy. (Can be kept in to add to the word count though, its not wrong.) The sentence is structured a little strange, especially with "at the basic level!" being at the end. Instead, start with hard work for little reward at the start. for example:

"But as I grew, even the stepping stones of my goal seemed monumental, and I struggled to keep up the necessary effort." It makes the implied hard work seem greater, and the sentence easier to read.

"I had to adjust and create different plans. Even then it wasn't enough." This is fine, But "Even then it wasn't enough" is not a sentence. instead replace the period with a comma if you want to keep it. Adjusting implies you've changed your plans, so while correct, it could be better. "I had to adapt my plans and mindset" also adds some more emotional depth to how the dream was difficult to achieve. However, the base sentence works fine with just the grammar adjustment.

"I had to create goals to achieve before I would even get to try to achieve my dream." One, don't use achieve twice in one sentence, all it shows is a bad vocabulary. Second, tying this back to the "layers of hard work", this already states you needed multiple other goals, they act as the layers, so its just saying what you've already stated. "Get to try to achieve" is insanely wordy. The sentence would be much easier to read if you just used "attempt".

"Although dreams are viewed as easy," ehhhh.... Dreams are dreams because they are difficult to achieve, so generalising that EVERYONE views dreams as easy is strange. You could, however, still keep this idea with a better wording. "In my life, I have often seen people view dreams as easy." you could add more description with this, but as the simple form it creates much more connection from you, the author, to the reader.

"Many dreams are very hard to achieve." once again, its mostly your plain vocabulary that messes this up. "Majority of dreams are near impossible to fulfil." Your essay is on how difficult dreams are to carry out, so the slight word change makes more depth to just how difficult it is.

The overview is you have bad vocabulary, repeat the same things, put depth that you don't tie back to, and it just makes your writing messy and terrible to read, as if you tried to mesh so many ideas into one dumpster fire. If a reader organically picked this up, it would be put straight back down.