Catches Tb. The germs get to the lung. The body responds. If there is enough germs a fight ensues. Symptoms are usually absent or mild. If not eradicated, the germs are kept in check and go dormant. Sometime later, even many years later, they can break out and cause active infection in the body, most commonly the lungs.
LTBI. You can get it check with your doc now and 3 months later.