I'm not sure what you mean. The only limiting factors are:
• your own ability to absorb information
• the quality of your instruction materials
It helps significantly if you are familiar with any other programming language, but even if you are not a couple of strategies can help:
• identify areas you wish to learn, such as "flow control", "functions", "classes", "formatted input and output", etc, and study the basics of those things.
• Google around specific tasks you wish to accomplish and see how other people do it on C++.
SO and Rosetta Code and GerksForGeeks are all prominent sites that cater to these things.
Also, remember that there will always be things to learn. Focus on a basic proficiency then add on to that.