Phase 1: Proof of Concept

This is my 2nd week of learning python. I wanted to do a solo project for practice. Yes the code is really sloppy and poorly optimized. But that's why I'm here.
This is a basic version of a conversion calculator program that can only convert to/from meters and kilometers. I also prettied up the code and output with comments and color. Gonna need a lot more repetitive work to get the code efficient. 17 length options = 289 different cases. Just for the length alone, not including volume or mass yet. Gonna be a lot of work but I'm stuck wondering how I can optimize this better as I am new.