A lot of people know what immaturity is. But do we understand what maturity is? Is it to be serious? Is it to be adult like? If it is, what does it mean to be an adult? It doesn't mean to have a family. Yes being an adult could be tied into having a family but that isn't what maturity is. You can be immature even if you have a family.
Maturity is finding yourself first. It's knowing that you're going to be OK alone. It's knowing that you can be independent and you don't need another person to control your happiness. It's knowing what you want right now. You may still be confused in the future about what you want, but doing what makes you happy is growing up. You mature more and more as you start to put other people's needs before yours which ties in with family. When you become a mother or father, you put your children's needs before yours. You do whatever it takes to make them happy even if that means more overtime or less sleep. You do anything to support your kids, though there's a difference between immaturity and incorrectness in parenthood. It's not immature to overwork yourself, but that is incorrect. You need to be able to stay healthy to take care of your kids.
You never stop learning how to be mature. Even when your old, you will still be maturing in different ways. Another maturing way is to be proud of yourself. It's when you don't need to brag about your accomplishments to others because knowing what amazing things you've done is enough. If you do things to brag to others, how is that affecting you? How is that personally making you better? As I said in the first paragraph, you should do what would make yourself proud because it's for you, not for others. Only you will remember your achievements. Only you will be able to make yourself really feel proud of yourself. Only you will be able to become stronger because of your goals. Sharing the news and bragging about your accomplishments are two different definition. It's not bad to be excited for yourself so you share the news. But again, you're sharing the news because you are proud, not because you want others to be proud of you.
Being mature doesn't mean you can't have fun. It just means that you know what is appropriate and what's not. You learn how to care about others yet you know how to care about yourself. Overall, everyone experiences maturity in different ways. Everyone goes their own pace. It is not a race between your friends as it should be a personal progress. It's your maturity. Do what makes you happy.