Web development is definitely preferable to mobile imo since you can do things like react native that creates native apps based off of web technology. Beautiful thing is that you can use one code base to make both apple and android apps... you can also use that codebase to make desktop apps with electron. On the other hand, if you wanted to use the native language, you'd have to do something like Java, or now Kotlin for android and then swift for apple.
What tools/tech stack are you using?
For a course last fall we used Apache server and I used PHP for the backend stuff and Mysql for the DB. I did all this on my surface pro 4 though and not my mac.
I'm looking to move from PHP to python as It seemed more flexible/popular and I'm not trying to become a Developer I just want to continue to keep my technical skills sharp as it helps with System design when working with Architects.