Why is that in my lower jaw the front teeth are twisting inside? what should i do to keep them straight so that they don't twist?

Crooked teeth ?: They may be crooked from periodontal disease, crowding and a poor occlusion (bite) or upper\lower jaw size discrepancy. See a dentist who can evaluate your periodontal (gum) health and discuss the possibility of orthodontic treatment.

At 28: At 28 crowded lower front teeth are one of the signs of a malocclusion. Once teeth have begun to shift the process is progressive. Please ask your dentist to refer you to an orthodontist for an evaluation of your malocclusion.

See dentist: An examination is necessary to determine why your teeth are shifting.... Natural movement due to aging, periodontal problems, bite problems? Hard to tell over the internet. At a minimum, if your teeth are healthy, an orthodontic retainer can be fabricated to keep them from moving any further. Make the call for an appointment.