If you want to extend that out to the full 10C change, that happened between ~17.5kya and ~11.5 kya - a period of about 6,000 years. You could extend that back to 19kya if you are generous and count from the very earliest glacial retreat, which is about 7.5kya

Moreover, there was massive acceleration in the glacial retreat after 15kya. That's what really marked the start of the end of the Ice Age; the vast, vast majority of the melting occurred between 15kya and 11.5kya.

And as noted, there was a massive warming event, that I literally linked you to in my post and that is visible in that graph you linked to, that saw 3 C of warning take place in just a couple centuries.

The idea that the climate only changes very slowly is actually false, and it is the sort of thing that no one with any real comprehension of science claims. It can happen quite fast; 1 C variations in temperature in a century are common, and 3C in a couple centuries has happened.

I'm not sure why you're lying about this, other than because you don't want to admit you're wrong. Even the graph you linked to shows you are wrong.

https://en.wikipedia.org/wiki/B%C3%B8lling%E2%80%93Aller%C3%B8d_warming