Emily pointed you to some great tips on how to improve your swing. You might also want to work with a pro that both teaches and fits clubs. That person can tell you when is a good time to move on from "the department store" brand. That will include both your growing skill level and when the clubs are holding you back.

Based on swing characteristics you can't change about your body, an incorrect length of shaft will make it harder to not dig the toe or heal instead of cleanly striking the ball. The shaft's characteristics will affect getting the face to the ball. Too heavy/light, too much/too little flex. Club heads may not have an appropriate loft. Each of us will have different irons we can hit and then switch to hybrids/fairway woods. The optimal driver loft is not just the rated loft but is also variable by the dynamic loft - do you hit up or down on the ball? If the box set is far from what you need, your pro may make a recommendation to get fit earlier than later. Ultimately, the club should accommodate you and not you adjusting your swing to fit the club.

All of this will be important to you at a fitting, but achieving an on-plane swing with contacting the ball in the center of the face is more important. No club can fix a severe slice, hook, and fat or topped shot. That's all in the swing mechanics. Good luck in your journey.

Charlene,
Starting out with a "beginner" set of clubs is a good way to start out in golf, but at some point you may want to upgrade. There is no right or wrong time to upgrade to new clubs, but when you decide to upgrade be sure to go through a fitting. When you go through the fitting process the end result is a set of clubs that are setup for your swing. A simple way to go through a fitting (at no cost) and have the opportunity to hit some Titleist clubs is to attend a Titleist Thursday event. Use the "FITTING" menu option at the top of the page and search for an event near you (you will need to wait until summer though).

Take some lessons from a good instructor. Let them tell you when you are ready to invest in fitted clubs