“What if I don't marry? How would I survive in old age alone?”

Another soul answered...

marriage will not guarantee you not being lonely in old age. a lot of people marry and are still lonely. you can marry if you find someone you are willing to spend your life with. as for if you're alone or not there are always hobbies and interests that can occupy most of the time of your day and you can also be a part of a community and/or find your people.