Best language to start with?

for web development specifically, you're best off learning to do some dynamic web page stuff with html + javascript + css to start. you probably want to play around with that for a few months if you don't already have a programming background. make incremental games for the browser or a tool for a game you like or something

once you can get something working with that, look in to some web frameworks (react, vue probably the nicest for beginners). do the same projects again using those frameworks, see if you can improve them, do it faster, make it feel nicer to use.

if you just mean programming languages in general then probably python for scripting, c# for more enterprise style work