Good start! Comments attached, see me if you'd like to discuss.
I think what you have here is a good start. You're definitely very passionate about the issue—that's good! It's a 1st year writing class, and unless you write about something you care about, then these assignments are going to feel like an empty exercise and it's not the best use of anyone's time.
Still, it is a bit long. Not that word count is the be all end all, but a good rule of thumb is that if it comes in really short of the minimum word count, you might be doing too little, and if it comes in really far past the word count, you might be doing far too much.
This is an issue that I see some of my students struggle with when they write about something that's really important to them. It makes sense—this is your argument to make and you absolutely know it better than anyone, and I can see that confidence in your writing.
But I'd say to try to think a little bit more closely about the specific change you want to make in your audience, and first, really, who your audience is. And let that help inform the two, maybe three things you choose to address in this letter.
There are some mechanical issues to tangle with, but at this point I'd worry a lot more about higher order issues first.
Please feel free to reach out or stop by my office hours before you turn in the final draft (chatting in person is just about always a more efficient way to work on this sort of thing). Thanks!