Take care of yourself first.
Life's most important moments, the ones who shape us and determine our success or failure by our own definitions largely occur when individuals are under pressure and stress. While life is full of second chances if you can't perform what you need to in spite of outside forces it will be hard to succeed. Therefore, the first and most important thing you can do is take care of yourself.
If you can manage that, You might be able to take care of another person.
Do not seek out a person who can't take care of themselves. They need to be able to do that. Look for a person who needs support because they want to accomplish great things and be a great person. Being great does not mean famous - in fact most great people are not famous. Great people horde wisdom, resilience, strength, kindness, and love. They may be wealthy, and there is nothing wrong with that but be skeptical of people who's main store of wealth is money or money-like things. As the saying goes: "some people are so poor all they have is money."
Being great is a form of excellence; excellence in the context of your peers. Excellence should be without harm and provide something for posterity. Being great is excellence in spite of your former self. Being excellent at things takes sacrifice, and sacrifice requires vulnerability. When you are vulnerable, reality has a tendency to knock you down. It is in those moments that a person needs care.
You can provide care if you possess empathy, strength, kindness, and love. You can only provide love where there is respect and a mutual understanding that two people (or more) can do more than a single person. You can love anyone. If you meet truly great people you will notice that the people around them tend to also be great. This is no coincidence.
Caring for yourself is more than most people are capable of, and caring for another person is even more unlikely- do not kid yourself, it takes great skill and perseverance to take care of just yourself- and it is also enough. You will have massively improved the state of the entire world just by taking care of yourself. If you stop right there you will have been a great success in life. You will have made the world a better place.
Adding the ability to care for another person is more difficult. So much suffering is caused because people just don't care for themselves. And much suffering is caused by people who try to take care of another person when they can't care for themselves.
If for some reason though you have found strength, courage, and tenacity enough to take care of yourself and another person, you might be able to share in the care of another person.
There are many people who need care out there and many ways to provide it, don't get bogged down in the specifics of who, what, or where. This activity is a form of wealth. As such, don't give more than you have, and don't overcommit. Having a child, taking care of an elderly family member, providing for a community are not small endeavors. If you don't have wealth then you have nothing to share and thats okay - build wealth first. I meantioned this earlier but do not fall into the trap of thinking that wealth is money. It's not. Many people think that money can solve all problems - it doesn't, and it can't. As I heard it phrased one time: "Money is to provide for family, and thats it."
If you can take care of yourself and another person (or a few), you have built a family. "Family" is not a genetic thing. It's not a tax status. It's definitely not a workplace. A family can be anything where people take care of each other, provide love, work on things together. It is different things to different people and people take different things out of it. Families are important, but people in a family are still individuals and should be treated as such. Those individuals do need to understand that they hold a place in a family, and that family itself is important and more important than any single individual. Families should be respected and patriarchs/matriarchs of families should also be respected. Again, it is not easy, simple, and there is a lot of personal sacrifice being made. There is a reason why so many mothers say the "labor is the easiest part of having a child."
If you've read this far, you can likely extend what I've written to the next natural step... some people have built so much "wealth" in their lives that they can extend it to communities, cities, regions, and even the world... and I am explicitly not representing this to mean government or organizations. There are many forms or shapes that it could take. Government, companies, non-profits, etc are not the only embodiments of sharing wealth. I'm not in a place to talk about that because I haven't done it yet. I have been able to take care of a family, and I contribute to our community. I don't presume that a greater scale is easy or intuitive.