using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var threeMonthsAgoDate = DateTime.Now.AddMonths(-3);

        List<DateTime> dates = new List<DateTime>

        {

            new DateTime(2022, 01, 05),

            new DateTime(2022, 04, 05),

            new DateTime(2022, 06, 01),

            new DateTime(2022, 07, 05),

        };

        var result = dates.Where(x => x >= threeMonthsAgoDate.Date)

            .ToList();

        Console.WriteLine(String.Join(Environment.NewLine, result));

    }

}