Extroverts people enjoy interacting with people and they are full of energy. They tend to be enthusiastic, action-oriented individuals. They like to talk and be amongst people.
There is nothing wrong be introverted, the only difference they are more independent of their social world, therefore, they need less stimulation than extraverts and more time alone.
Socialize is a good way to keep your brain active. You don’t need to be a social butterfly or the life of the party. Talk to people, go somewhere different. Don’t talk just about specific subjects. Talk about a movie you watched, a trip you went, discuss economy, politics, a book you read.
Join an interest group. Choose something you like to do and join a club or group to meet people with similar interests as you. This can be a hobby, a discussion group, a sports group. Talking to people with similar interests will get you using your brain and your skills. When you express yourself you are using different areas of your brain: you are converting emotions, images, memories and translate into words.
If you don’t know how to meet new people, the Meet Up (https://www.meetup.com/) website can be a good start. You can also check any cultural events happening or volunteer work.