Please keep in mind that learning an instrument, or music in general, is a long process, or in fact, it is a non-finishing journey. The more you learn an instrument, the more you find out how much more you want to learn.
You definitely won’t be able to master any instrument in a matter of a couple of years, but if you show commitment and discipline for practice, it may take you between several weeks to a few months before you can start playing simple songs correctly.
Some people have the ability to learn certain skills faster than others. For instance, some people pick up the techniques of the right hand faster than others, while others may excel in learning notation and rhythmical forms faster.