It is the 23rd version of the software. First illustrator version was released on 19 March Adobe illustrator cs6 version was released on April 23, It was the 16th generation of Adobe Illustrator. This version may be a bit older.
Size Adobe Illustrator CS6 can the right option to figure out.
How To Get Started with Adobe Illustrator CS6 - 10 Things Beginners Want To Know How To Do