You have made great progress. Sadhu! Sadhu!! Sadhu!!!
You are right. Asmi mana goes away only at the Arahant stage.
– However, asmi mana will also decrease gradually as you make progress. It is not a sudden drop.
For example, a Sotapanna Anugami starts losing all ten samyojana gradually as he/she makes progress.
– Then the first three samyojana (sakkaya ditthi, vicikicca, silabbata paramasa) will cease in one thought-moment. That is when one attains the Sotapanna stage.
– However, by that time the other 7 samyojana would have decreased in varying degrees too.
– Then kama raga and patigha will cease to exist at the Anagami phala moment. By that time, the other five samyojana would have decreased in varying degrees.
But it is asmi mana that is usually eliminated last together with avijja. There are some who have eliminated rupa raga and arupa raga but have the other three (mana, uddacca, avijja) remaining to some degree. Those there are the last to go away at the Arahant stage.
So, I would not worry too much about asmi mana. Hopefully, you will see it reduce too gradually.
By the way, one loses asmi mana when one fully realizes the anatta nature.
– The first step is to “see” the anicca nature.
– The current series of posts on the Five Aggregates discuss these in a systematic way:
“The Five Aggregates (Pañcakkhandha)“