I would strongly advise you to do some work on the install side first. This comes from personal experience. I installed for 7 years as a journeyman electrician before I got the laptop and learned the programming. What installing teaches you is how and why you install damper actuators a certain way, how and why you wire up a 3 wire actuator and a 2 wire and their differences, and very importantly, where to properly install a sensor in the system.
Having an electronics and electrical background have truly been a boon to me. It helps me troubleshoot much more easily.
I did the install thing, the original programming, commissioning and checkout thing, and now the full time troubleshooting thing and I couldn't have done it without this background.
BTW, I love my job. Troubleshooting and fixing stuff others can't get, solving a problem and seeing happy customers is very rewarding!