64 learning to write code is relatively easy. The hard part is learning to write good code (Spoiler : No one will ever succeed in this).
Another problem may arise if you use windows, as for some programming languages it can be hard to get everything it needs working on windows.
I suggest to just pick a language and try stuff out if you learned the basics of one language you know the basics of pretty much every language.
Javascript can easily be written. if you have firefox you can click on dev tools and open a scratchpad(shift+f4) that is a reasonable editor and allows you to execute the written code directly on the page.
If not you can just write a .html file and open it in the browser, this should also execute any javascript that you write in said page. This also allows you to play around with html and css.
Another option is of course to go with computercraft. Lua is a fast, small and above all very easy language to learn due to its very easy syntax. On top of this, playing with turtles that then react with the world is a lot better motivator then just seeing some text appear on the screen. There is also an edu version, which if I remember correctly removes the need to type anything, allowing you just care about learning the logic that programming needs rather then the syntax of a language, which makes it an even better choice.
Another but more expensive option is to buy a lego mindstorms. Just like the edu version of CC you don't need to write code by hand and instead use "blocks" that tell what the lego robot need to do. I have no experience with the newest version (EV3 or something) but if the software is anything like the one from the NXT it should be easy to use. You simply place blocks and connect them, the robot will then execute them in order. On top of that each block also can take some nicely labeled input from other code blocks, which you can easily accomplish by drawing lines from one block to another.
Other languages that you may want to look into are python and php. php because it still gets used a good bit and python because its syntax is relatively simple and will force you to indent well, which though easy to do makes it a real pain if you don't.