Filter nested objects javascript

I can’t get to solve this exercise

The called function receives as an argument an object ‘guests’, in the object we have objects that represent the guests at a party where they all have an "age" property.
You must return the number of guests who are under 18

In the following example it should return 2

I tried to solve it in several ways, at the moment it goes like this:

function howManyMinors(guest) {
    let guests = {
    Luna: {age: 25},
    Sebastian: {age: 7},
    Mark: {age: 34},
    Nick: {age: 15}
    };
      
    var minors = 0;
    for(element in guests) {
        if(Object.values(guests) <= 18) {
            minors ++;
        }
    }
    return minors;
}

>Solution :

You aren’t using the incoming parameter. There is no need to define an internal object inside of the function.

To compute the number of guests who are under 18, I would do something like:

function howManyMinors(guests) {
let minors = 0;
  for (const guest of Object.values(guests)) {
    if (guest.age < 18) minors++;
  }
  return minors;
}

howManyMinors({
    Luna: {age: 25},
    Sebastian: {age: 7},
    Mark: {age: 34},
    Nick: {age: 15}
}); // 2