I am 32, and i am in my final year of master's student. after this is done, I will probably start Ph.D. why am I in interested PhD in ML even though I know I am not that kinda smart enough compared to my peers who can finish their master's in 1 year only? I love studying and researching and I wanna be a researcher in this field. I think you should ask yourself why did you after Ph.D. at the very first place. Because I am afraid you cant finish your Ph.D. later and struggle with what kinda job or career you wanna pursue. If you want to engage in academic field, then taking PhD is a better choice. about ML industry for PhD, I think it depends on the career choice that would be opened whether you wanna work in Germany or outside.