Hi there. :)
Like you, I'm a 19 year old who works my tail off to keep my horse. I work at the barn four+ days a week, and I am also a full-time college student. Because of it,I can't afford lessons. I am a 100% self-taught English rider and have been riding for about ten years.
I'll tell you what I do to make riding for myself and my horse as safe and enjoyable as I can. I read, a LOT. I read about flat work, jumping, training, anything. I read a lot about lightness and connection. I also do a lot of watching. I watch videos, other people ride, and audit lessons when I can. And of course, I stalk Horse Forum.
There is nothing like hands-on, direct teaching from an instructor, but some of us have to do what we have to do, and make the best of it.
So, I suggest you do the same. Consider subscribing to Dressage Today or Practical Horseman. Tons of good information in those.
Like I said, I am completely self-taught and currently own a coming five-year-old Thoroughbred who I have had since she was a yearling. I saved and saved and saved to afford two months training for her so she could have a great start. Since then, I have been reading, watching and listening to get us to where we are now.
Here we are today, jumping 2'3 for the first time, only the third or so time we have cantered a fence. Cantering 2'3 - YouTube
We aren't perfect, but for a young horse and a self-trained rider, I think we are pretty great.
The point of this is to let you know that, even without lessons, you can become a safe, confident rider. Don't let other people get you down! As long as you work hard and are determined, you can become a fine jumper.
Keep your head up, and keep working! Take videos and pictures whenever you can and get critiques. Wade through the ugly comments and focus on the constructive ones.
So, here is my critique of your video.
You need to lighten up your seat. It seems like you have a great full seat canter; now just work on that half seat! I am working on that same thing. I love full-seat but hate riding in half-seat. I think I'm a dressage rider at heart!
Also, work on some inpulsion from your sweet horse. Do lots of transitions to get him up on his forehand and working from behind.
Even though the jump is small, work on having a bit more fluidity in your hands.
Also, maybe try to build some jumps. A length of sand-filled PVC is a cheap and easy way to make poles. Be creative with jump standards! Anything that will support a pole but also allow it to let the rail fall will work, so long as a hoof or leg can not get caught it in. Upside down buckets are great!
Sorry for the VERY long winded post. Cookies for reading my life story!