hi
you will eventually learn other things, but thismight help
FIRST OFF in a non pressurized airplane, anything more than a 500 foot per minute descent rate can be uncomfortable to the average person
so, limit yourself at the most to 500 FPM and this would take 14 minutes.
trouble is your are already too close to accomplish this as chilli monster has pointed out that rate of descent and speed/time.
SO...you should have started 14 minutes from the field assuming straight in to the runway.
JOINING THE PATTERN is something different and you might be able to do it at 500 fpm.
in the future you will understand better, but YOU have to decide how to handle your plane and the rate of descent to use.
In a jet we could descend easily at 6000 fpm (though not most efficently)...so there are many factors and as the others have indicated YOU HAVE TO KNOW MORE TO ASK THIS question intelligently