Replacing a missing tooth/teeth helps in grinding food(molars, except wisdom teeth) and facial expression and esthetics if it's your front teeth.
Next Steps
If your teeth are loose, get it examined by dentist, if it's in early stages of deterioration it can be resolved by proper treatment.
Health Tips
At your age good dental health would help in good digestion and overall health, so visit your dentist and consider all possible options of replacement and strengthening your remaining teeth.