What are the methods of cleaning carpets ?
Vacuuming is the preferred method of cleaning carpets. From TLC, carpet cleaning tips •Carpets need to be vacuumed once a week and more often in areas of heavy traffic. Frequent vacuuming prolongs the life of your carpet by preventing a buildup of gritty particles that can cut carpet fibers. Every few weeks, take a little extra time and use your crevice tool for cleaning around baseboards and radiators and in other hard-to-reach places. •To vacuum wall-to-wall carpeting, divide the floor into quadrants and vacuum an entire quadrant before moving on to the next. •Take your time when you vacuum a carpet, especially a plush carpet in which dirt is sure to be deeply embedded. One pass with a high-powered upright is not enough. Go over each section of carpeting several times, and work slowly to allow the suction to remove all the ground-in dust and dirt. •Pay special attention to the areas where people sit and move their feet. Vacuum these areas of heavy traffic with a crisscross pattern of overlapping strokes. •Soil retardants can be applied to new carpets or to newly cleaned carpets. Follow manufacturers' advice. Apply soil retardants only with professional equipment using the recommended application techniques. •Add baking soda to the bag in your vacuum to fight odors.
If it's only 3 months old you'll be fine just vacuuming it regularly. Don't go down the road of shampooing it until it's a bit older, they're never quite the same afterwards, regardless of what claims might be made by carpet cleaner companies.
I would advise you to rent a carpet cleaner professional so that your carpet stuff is looking like a novel.