public class Student
{
    public Guid Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public DateTime Created { get; set; } = DateTime.Now;
}

public class Goal
{
    public Guid Id { get; set; }
    public string Name { get; set; }
    public DateTime Created { get; set; }
    public DateTime? Started { get; set; }
}

public class Objective
{
    public Guid Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
}