Any advice for more of motivation and how you get disciplined?
Given your age, the answer is easy. Join a sports team/club. The type of sport doesn't matter, but moving around, getting a social group and disciplined does wonders for both physical as well as mental health. Also, could help fix any procrastination issues too.
As a bonus, if you do it for say, 2-3 years, they you will likely get pretty decent at it too.