Can a person become fluent in Esperanto in under one month?
I hope to attain fluency in Esperanto in less than one month, do you think this is possible?
But I do think one month is enough time to have all of the basic grammar rules memorized, have a good basic vocabulary and to be reading books with the help of a dictionary. There are 5258 official words (~10,000 official and unofficial words combined) in Esperanto - that's much smaller than English's 171,476, but it's still probably too much to commit to memory in one month.
Keep up the enthusiasm! Practice listening to podcasts (I recommend Kern.Punkto and Esperanta Retradio), watch some simple videos (I recommend Esperanto Variety Show, Evildea, Mazi en Gondolando and Pasporto al la Tuta Mondo), try reading a simple book like Gerda Malaperis, and once you complete the tree here on Duolinguo check out Ekparolu which lets you get 10 free Skype sessions with an experienced Esperantist.
Well... almost absolutely. What do you mean by fluent? How many hours a day can you put into this? Do you know any fluent speakers who can help you?
My experience - after a month of regular and dedicated learning, I could slowly but comfortably read and write basic Esperanto with a dictionary ... and with plenty of embarrassing mistakes which ultimately made good stories.
Short answer - no. Not if by fluent you mean able to talk unhesitatingly about any topic or to read and write about any concept.
Slightly longer answer. Can you pick up the majority of the grammar, a decent set of vocab and be able to undertand and make yourself understood in the basic concepts one might ordinarily talk about. Maybe.... probably. But... Esperanto may be regular and it may be logical and it may be comparitively easy to learn. But it is still a language - a complete language you can discuss anything in. It took you 15 years to be truly fluent in your mother tongue, it is highly unlikely, even with dilligent study you could achieve that in a different language in a month, ore even a year, no matter how easy to learn that language is.