Do fun projects! After my freshman year of college I switched from biology to self-taught programming, and I tried to find projects that were the intersection of those two interests. Genetic algorithms, neural nets, and Boids took me a couple weeks to implement each, but the internet is full of good tutorials and the end results are quite nice to look at. Anyway, yeah after self-teaching for two years, I realized there's a level of competence that I probably wouldn't reach if not for school, so I transferred to UC Berkeley to get a degree.

Best of luck! It will be hard, but if you program every day for a couple months you will absolutely be on your way to becoming an engineer!

Genetic algs: https://blog.sicara.com/getting-started-genetic-algorithms-p...

Boids: https://processing.org/examples/flocking.html

Neural nets and deep learning: http://neuralnetworksanddeeplearning.com/chap1.html