“I might be 90 years old, but I'm still young at heart!”
You're talking to an elderly neighbor. She says that she is 90 years old, but she jokes that she still has a lot of energy.
I might be 90 years old, but I'm still young at heart!
Sometimes you want to state an opinion, but you know that the people you're speaking to have a different idea in mind. For example, you might think that Paris would be a bad place to live. However, you know that a lot of people like Paris. In that case, it can be helpful to acknowledge the other opinion like this:
Paris might be popular, but I wouldn't want to live there.
Or if you're trying to convince your partner to buy a more expensive pair of shoes instead of a cheaper pair, you can say this:
They might be more expensive, but they'll last longer.
Use the phrase "young at heart" to describe an older person who acts or feels like a young person. For example, an elderly person who enjoys dancing, makes funny jokes, or has a lot of energy can be called "young at heart".
"Young at heart" is a positive phrase. If you want to talk about someone old who acts young in a negative way, you can say something like:
He doesn't act his age.
He still acts like a child.