I can understand your lecturers point. PHP is not a great first language. C or Java would give you a broader understanding of programming in general.
As for being a dead language, PHP is definitely not.
I've just noticed that you say you want to do your final project in PHP. Well PHP has the ability to import Java objects just as if they were native PHP objects...which means you can have a 'high power' compiled back end with a flexible, fast interpreted front-end...cool huh