As an adult I have attempted to learn Italian and French.
I did French for 3 years at school so I had an advantage there, however, decided I would rather learn a totally new language as already speak two languages apart from French.
I had great difficulty learning as an adult.
I was not so good at studying when I was at school, however, as I age, I am obviously worse than I was!
I ended up stopping the course as I just could not remember things and thought there was no real need to know this language anyway.
The language I speak German, landed me in jail once when I went to Germany, so I do not think it is necessary to know a language whilst overseas in many countries anyway, so I gave up.