If you're teaching yourself then it depends on what sort of projects you find interesting. Staying engaged is important.
If it's websites, try Javascript. Freecodecamp used to be good but I'm not sure anymore. A word of warning that this is a fast moving space with lots of different trendy frameworks etc.
If you like to see results quickly, try python. This is also good for data analysis.
If you don't mind a little longer to get going, but are wanting good skills for industry then I'd say c#. This teaches good skills for app development also.
And if you really really want to know how things work and have great patience, then C. It's bare bones and painful to code in, but you learn a lot. Not for the faint of heart.