Upgrading my license

Hi everyone this is my first time posting on or creating a thread. I have a question or maby a series of questions. Ive been working offshore for nearly 10 years on a 200 ton vessel. I have an OS, AB and im a 200 ton mate and have been for about 6 and a half years, somewhere around 1540 days of sea service with the .5 days added due to the 12 hour working days. My first question is, I want to upgrade my license as far as I can before before I’m stopped by required sea time and as far as the STCW of equal grade I know of all the training and assessments that lay ahead of but that will only be a matter of time. I’ve done quit a bit of research and maby I’m overthinking it or I just tend to confuse myself, I’ve read other forums and reviewed the checklists And I’m not sure if I’m eligable for my 3rd mate I know I would have a tonnage limitation until I work on a vessel for X amount of days but I do still get confused on what license I am eligable for with my 1540 days if anyone has any advice or if I’ve worded something wrong please let me know I am open to an sujestions and advice.