Is ancient greek like learning rocket science?
Having studied both rocket science and ancient greek, I would have to say I found ancient greek the hardest. One year of greek at school was too much for me and I gave it up for physics (which I hated). If you have already studied latin, then it will be easier. Greek doesn’t have a huge vocab, but everything about the language is irregular. Greek history is extremely interesting which helps, as do the many English words which have Greek roots. There may be dark recesses of the civil service where classics are still highly regarded, but in the modern world employers expect your studies to have some relevance. I would recommend checking out the UCAS site to see what graduates do when they qualify. The UCAS site will also guide you on entry requirements etc.