Music is the one art form that surrounds us perhaps the most. It is easy to consume music, but making music can be so much more rewarding. There are lots of ways you can be involved in making music: playing an instrument, singing in a choir, singing solo, or even making songs. All forms of music making make you practice your creativity, because any decision on how to sing or play a song is based on your own imagination and artistic taste. Making music does not mean you have to be supremely musical. A lot of people who sing in choirs would not be able to stay in tune by themselves, but surrounded by more musical people they can sing well.
There are also choirs for all levels of singers. If you are interested in joining a choir, find out what kind of choirs there are in your area. Most Christian churches have choirs where anyone can join, but depending on which country you live in, they may also be non-religious choirs that are open to anyone. Choirs are a fun hobby not only because singing together feels great, but it also gives you the extra benefit of meeting lots of new people. If you like to sing alone and to perform, a fun way to do that at amateur level is to sing karaoke.
If you are afraid to sing in front of strangers, rent a booth with friends, and get used to singing to an audience there. And once you gain confidence, you can sing in karaokes in front of strangers as well. Learning to play an instrument as an adult is not at all impossible as long as you commit to practicing. Some instruments are easier than others, for example the guitar or the piano are easy to learn, and they sound good even if you cannot play well. If you would like to accompany yourself or someone else singing or playing a solo instrument, both guitar and piano are perfect for that.
There are lots of benefits from learning to play an instrument, that apply equally to adults and children. Playing or singing allow you to express yourself and your emotions, and to feel the emotions that different songs raise. In playing music you are even more immersed in it that when merely listening. And that means you are fully concentrating on what you are doing, which means that as long as you are playing or singing, thoughts about work and worries will stay far away.