Should beginner programmers use unit testing?

I have been learning PHP for several months now. It is not my first language, but it is the first language I have tried to use for real-life projects. Currently I am writing a web application that can be easy for experienced programmers but is rather hard for me. And the more I write it, the more I realise that I spend more time pressing buttons and entering inputs to test my code than actually writing code. I have heard about unit testing (and other kind of testing) and it got me wondering: does my simple web application need any automated testing or is it a complete overkill? Is unit testing something a beginner can learn or is it only something experienced programmers use correctly? And since I am writing a web application, can all its code be tested or only the small logic parts?

Thank you.