Yes, it’s possible, but you better be ready to commit for many many years for this to happen. And, even after all that time, you might not even gain 1 inch. It’s hard to tell as some people respond well to jelqing and some people require a lot more time and effort. Just be consistent and patient. Above all else, jelqing is a very healthy thing to do to your unit. It will make your dick stronger, harder, and most likely bigger.
On a side note: I personally think you are going above and beyond what is reasonably necessary with 20-30 minutes of jelqing. Having only started PE a few weeks ago, you should be focusing on developing good, quality jelqs as opposed to doing 20-30 minutes worth (which is probably pushing 500 total). Don’t rush yourself into such a high volume when you probably don’t need it.