How hard would it be to develop an app for Lemmy having only limited programming knowledge?

I understand how to code... To an extent. I know syntax and can solve problems given a set of tools (such as source code, functions, etc). I've made mods and basic programs (literally and figuratively), but I've never messed with internet stuff other than networking and mostly on the hardware side.

I don't expect to make anything that will catch on, but maybe I can make a perfectly adapted thing for my own personal use. Would it be a good learning experience, or would jumping from modding and making, like, a DnD character sheet generator into making a front end for a website/service be a bit of an undertaking?