setState(() {
  userAge = calculateAge(birthDate, today);
});

class _AgeResultWidgetState extends State<AgeResultWidget> {
  UserAge? userAge;

  @override
  Widget build(BuildContext context) {
    return Text('Years: ${userAge?.years ?? 0}');
  }
}

String formatted = DateFormat('d/M/yyyy').format(myDate);
// "5/3/2025"

ListView(
  children: [
    Container(height: 60, child: Text('Item 1')),
    Container(height: 60, child: Text('Item 2')),
  ],
)

ListView.builder(
  itemCount: courses.length,
  itemBuilder: (context, index) => CourseCard(course: courses[index]),
)