I got my first horse 11 years ago when I was 15.
I had been riding once a week at my riding school, and had spent most of my school breaks at riding camps. For some reason, I thought I knew what I was doing :) so my mom bought me a 4 y.o. gelding. (No one in my family is a horse person besides me). Him being a Norwegian Fjord, I would say he was probably slower than a TB could be, and not as "bouncy ball" flexible, as a longer legged horse, but I can tell you - these guys are STRONG. He was saddle broke and had been backed, but not trained.
I thought: "I want to be able to grow with my horse - I don't want a horse that is dead quiet and lazy, but one that has a little spunk to him". At first I thought all I would want to do is go on romantic trail rides, and have a great buddy.
1. He had never been in a stall before in his entire life, so the first day I got him (and I was oh so proud) he not only stepped on my feet about 7 times, but also ran out of his stall before I was even able to turn around and close the door!
2. It was September, and Fall in Germany usually gets quite rainy and wet! I quickly noticed that this "romantic" idea of only trail riding is not all that pink and fuzzy when the weather is bad and it's freezing.
3. We had a small outdoor riding ring that was super super muddy. I noticed that he wouldn't exactly listen to the aids like all the lesson horses. My dad and I would lunge him, and he would just turn his head out and run... I wasn't amused, but looking back, it was quite funny.
So I figured I needed help. I moved him to a large dressage barn, where I fell in love with dressage and started taking lessons with an amazing dressage trainer. (In Germany being a professional rider, trainer, breeder is usually an actual job. You have to train with a master and take theoretical coursework and then pass riding and theory exams at the national headquarters) - So I knew I was in good hands! Even though we were the odd ones out at my barn, since most people in Germany don't usually own a Fjord when they want to be successful in dressage, we kept up our lessons, and hard work.
It was so important to not only have the facilities to work him, but also the guidance. My trainer being onsite pretty much every day was probably the biggest thing I could have ever, ever asked for. Not only would she give us our lessons, but whenever I was riding, and she was riding one of her horses in training, she would give me advice whenever she saw I needed it. When she saw that my boy was getting through with something I wasn't able to correct, she would get on him and settle it then and there.
I know that I could have progressed much faster if I would have had a schoolmaster - I could have showed more, won more, and probably would have gotten more recognition by other riders at my barn.
However, I got to know my boys character. I had plenty of tears, it took us over a YEAR to come home from a trail ride TOGETHER! I still remember the day - It was super hot, I had just had a great dressage lesson and I knew he was happy but tired. That's when I decided to take him out and go for a ride along the fields. As I picked up a trot and a canter, I remember thinking that this is the best day I have ever had in my life. :) I am smiling just writing this.
Since that time, he has been a "Special Olympics" horse, he moved with me to college and back, he has survived bad colic surgery, I took him from Germany to California when I moved, he has done cattle drives and stood in the Pacific Ocean, we've won plenty of dressage ribbons (will be doing 2nd level this year), and last summer he moved with me to Ontario, Canada.
Even though I know he does not have the body or movement to make it much higher in dressage, he is the perfect horse. People thought I was crazy when I told them I was taking my "Fjord" with me to California, but I know everything there is to know about him, and we've grown together.
My advice to you
1. Find a good trainer and listen to her advice - ask questions and ask for clarification.
2. Don't listen to EVERYBODY's day to day advice - it will drive you crazy. Be open to new knowledge, but like us, every horse is different and may think/function differently.
3. Try to ride as many different horses as you can. Your horse will start to cover up your weaknesses and you will start to take what your horse does for granted. I learn the most when I get on other horses - they show what I do wrong, and make me pay attention.
4. Let your trainer ride your horse. Not only does your horse need to learn precise/correct cues with clear reward, but you also want your horse to mature into a confident mount. A confident rider will be able to give a young horse that guidance.
5. Wear a helmet! No matter how hot it is, or how many people aren't doing it!