There is no limit for applying for Google adsense other than wasting your time if you are not prepared. You must have written at least 10-15 good quality hubs of at least 800-1250 words with good punctuation and grammar that must be featured hubs. Looking at your hubs, they are entirely too short and the grammar and punctuation is not very good. You may want to do some editing.
Google adsense wants hubs that they will be proud to put their ads on.