I've been studying greek for 4 years now and yes, it's hard. I do 4 hours a week but it requires a lot of work at home. The main difference form latin (apart form the alphabet, that you'll learn to read the first lesson and it's actually so much easier than it seems) is the grammar, that's quiet harder, and when in latin it's very strict, greek is full of exceptions. This for the down side; on the other Hand, i don't regret studying greek, greek philosophy and lliterature are the best, and studying the language will really give you a full knowledge of the greek word and forma mentis. So if you think you'd be able to dedicate quiet a lot of time to it, definitely do it, you're going to love it eventually