[mkhcodes]

As others have stated, start with an Arduino. Have fun.

But I would recommend as a next step is to find a component that is more complex than an LED or Switch and with relatively good Arduino libraries (e.g., a 2x16 LCD screen) and try to write your own driver for it (e.g., a library that does all of the handling of the IO pins), using the data sheet of the component to figure out how to use the IO pins. Feel free to look at the Arduino library source code (or libraries for other languages).

I have done the same, using Rust and a Feather M0[1] and am now finding it easier to look at the datasheet of the more complicated ATSAMD21[2] microprocessor.

1. https://www.adafruit.com/product/2772

2. https://www.microchip.com/wwwproducts/en/ATsamd21g18