Forgiveness of Sins - Red to White

"Im Yeheyu Chataeychem Cashanim" The Gemara in Shabbat 89B asks that the word "Cashanim" should be "Cashani" in singular rather than plural. The Gemara answers that it is a hint to "Years" that even if your sins are so vast as the years since the beginning of creation they will still become white like snow. the obvious question is when we are looking for a large number we can say as vast as the stars in the sky or the sand on the beach or something that reaches the billions not the years since creation which reach only into the thousands. We are obviously not referring to only a quantitative measure here but some kind of qualitative analogy. We can explain according to the derech of the Maharal, we know that once you do an avaira again and again it is much harder to stop because in your mind it loses its severity and second nature becomes a habit. The ultimate second nature is if you do something again and again since the beginning of time until the end of time. The Navi is telling us that even if you have sinned in a certain fashion and it has become part of who you are because of the repetitiveness of the the sin you can still be forgiven.