Is it actually possible to attain self-actualization?

It depends how you measure self-actualization. This is extremely subjective; the standard that one uses to determine if one has achieved it depends on the definition and measure that one chooses. There is no "official" self-actualization scale or standard. If you go through the self-actualization literature, you'll see that a number of different measures are used.

thanks a lot SIr, David Dunaetz 

In Maslow: The 12 Characteristics of a Self-Actualized Person (Huffington Post, 21 July 2015), David David Sze presented a selection of the most important characteristics of self-actualized individuals, e.g., Abraham Lincoln, Thomas Jefferson, and Albert Einstein, extracted from Abraham Maslow's book on Motivation and Personality (1954):

So, even if measurement would be subjective (and against the spirit of inquiry about self-actualization), there are pointers to balanced and wholesome living (and different "measures" can indeed be found elsewhere).

Yes.

HI: Maslow described it as a process of becoming so it would be very rare for someone to be self-actualized. Supposedly Maslow himself was asked if he was self-actualized, and he said no. I was taught in phd program that the idea of self-actualization is to inspire people to constantly try to become better. Many people think they are self-actualized but aren't. When I teach my undergrad students about this and ask who has self-actualized the majority of students raise their hands. So I would guess that people overestimate where they are on Maslow's hierarchy and that given the description, it would be more likely that someone older with more life experience would be more likely to reach the upper levels of the hierarchy. ERG theory is an improvement of Maslow and has been measured more often in research. You may wish to consider looking into that theory also. All that said, I don't consider myself an expert on Maslow and wanted to suggest ERG Theory as an alternative framework. Take Care, Sherry   

Dear Julfikar,

Past week you posed a question about RG score decreasing, and I and others give answers to your question. But now one cannot find neither your question nor given to it answers. I asked you, what has happened but you answer to my question was “Welcome sir”. Now you ask other questions. Where is the guarantee that with these questions and our answers to them will not became the same?

Yours,

Aslanbek

Can one be self-actualized? Depends, of course, on the definition you accept, but yes, one certainly can, and it is, of course, a life-long process.