I was a working student and held down a part time job at the same time.
It was definitely difficult, but when I went to interview for the working student position I made sure that she knew I needed to get a part time job after we got back up north in the spring. She and her barn manager were really good about working with me on that. And then when I was in my interview for my part time job, I made it clear to them that they HAD to be flexible with my barn hours if they wanted me there. I had one set day off a week from teh barn where I could work a full 8 hours, but otherwise I had to have all closing shifts and they had to be a little more flexible about my being 15 minutes late or not. That was just how it had to be. Luckily, it all worked out for me, but trust me when I say it is super difficult to do and you really HAVE to want it to do that. That being said, it IS possible to hold down a part time job and be a working student. Make sure, if you try that, that you get the show schedule in advance so you can let them know way beforehand all the weekends you won't be able to come in!
I know others have suggested college, but for me...well it just hasn't worked out. I've completed a year and a half, then took almost 2 years to be a working student then professional groom. I'm currently taking some time away from horsesand I attempted to go back to school, but it's just not the right time in my life for that. After this year long break is up, I'm going to go back to the horses, most likely. In the meantime, I'll be taking some lessons weekly to keep my butt in the saddle so I don't get too rusty. ;)
"Always be yourself. Unless you can be a unicorn. Then, always be a unicorn."