The character every beginner should start out with is Ryu. Learning Ryu first will give you a basic knowledge of the game. Ryu is an all-around player, having no blaring weaknesses. Ryu is a very defensive player, which is the first thing you’ll want to learn. It will develop your execution, defense, zoning, pokes, option selects, anti-air, etc.
After you get fairly decent with Ryu, you should switch to Ken. This will teach the the offensive side of the game. Rush-down, tick-throw, mix-ups, cross-ups, kara throws, and overall how to be aggressive.
This is optional, but if you want to explore the world of charge characters, learn Balrog. He is like the Ryu of charge characters (good all-around base) If you like charge characters, start learning other charge characters (Bison, Dee Jay, Guile, etc)
Once you are effective with Ryu and Ken, you should have an idea of the play style that you’ll want to play as. If you’re more defensive, start looking at defense-oriented characters (Guile, Chun-li, Balrog, etc) or if you want to play more of a rush-down style, start looking at defensive styled characters. (C. Viper, Akuma, Cammy, etc)
Hope that helps.