I think I'm starting to understand what my destiny is.
"I think I'm starting to understand"=「分かり始めていると私は思います」
"what my destiny is"=「私の人生とはなにか」
Example in context:
"It was only in my mid-thirties that I began to understand what I am destined to become."
★"destined to be~"とは"destiny"(運命)の動詞になります。