I think that many people have gotten the right answer about this. I think end the end you are really not a REAL expert but until you have spent considerable time studying the creature. Like snakeguy said learning there internal system and the way they work. Not just how to care for them and NOT the whole species, just 1 specific 1. Now obviously you can become a "expert" or "experienced" by learning but in the there is always more to learn. For instance i think i am starting to finally get good at knowing the cacellian species, specifically the Typhlonectes natans now i own 1 and i have spent numerous hours watching and observing and have even started keeping a journal. I have seen the internal workings of them and have even put a hand in disecting 1 and IDing the organs in it. NOW, i am not calling me a expert as i am far from it but i am defiantly starting to get myself into the realm of experienced and i am not even there yet.
Other than your map turtle that has been sick and your painted turtle that is too small to even sex yet, do you have any turtles? Neither of those two species are difficult to keep at all and if those are the only turtles you have experience with, you are far from an expert. To be honest, that level of experience hardly puts you beyond novice level, let alone anywhere near expert. 