If I attain a Master's degree, how do I refer to myself?
Solution 1:
Yes. If you graduate with a BSc or BA, you are a Bachelor of Science or a Bachelor of Arts respectively. Similarly if you graduate with a master's, you are a master, and if you graduate with a doctorate you're a doctor.
But it's almost unheard of nowadays for people to routinely refer to themselves by their academic title for qualifications lower than doctorate level (and that's becoming rarer too in my experience), so something like "After I graduate with my master's, I would like to..." might be better.
Solution 2:
What about simply:
When I receive an/my/the MSL degree, I would like to ...