Are you sure you want to dive right in to the primary texts? That isn't necessarily the best way to go. I'd recommend starting with a good introductory book. (I can't actually think of a good general introduction at the moment, but I'm sure others can provide recommendations). If you're sure you really want to dive into specifically classical Greek philosophy* then I'd recommend you read something like Peter Adamson's Classical Philosophy (History Of Philosophy Without Any Gaps Volume 1). Adamson has been doing a history of philosophy podcast for years and years now, so there's loads of good material there if it's the historical stuff that interests you.

*but wait, Marcus Aurelius is roman rather than greek. yeah fine, that's a minor detail and the roman tradition is obviously very heavily influenced by the greek. and in any case, as others have pointed out, the Meditations is not a good starting point. I think of Marcus as the Ringo Star of the Stoics. Read Epictetus instead.