I know HTML, a little bit of python and I know C++ what is a great language on my stage?

Answer 1

focus on mastering either python or c++

also learn html's friends: css and javascript

Answer 2

php, javascript

Answer 3

great language on your stage will depend on what field you would like to go ahead with if it's into Web development Perfecting HTML along with CSS, Javascript and PHP would benefit you in your future endeavours.
If core programming is where you would like to be in as in software testers and or software developers go ahead and spend more time with C#, C++ and Python.