This tweet is almost definitely fake, for multiple reasons.
According to the screenshot, the tweet was sent on March 31st, 2014.
Taking a look at Mr. Modi's tweets between Mar 30 and April 1 2014 reveals no tweets that contains that content.
The image linked uses the hashtag "#HSCresults2k17". It is HIGHLY unlikely that Mr. Modi would be tweeting using a hashtag regarding high school test results in 2017 in March of 2014.
A search for posts using #HSCResults2017 and #hscresults2017 returns no matching tweets. Other spellings do not return any results.
Dear HSC students please don't get upset with your results. Remember i am a chai wala & Arvind Kejriwal is from IIT Kharagpur #HSCresults2k17
is 141 characters:
While some Twitter accounts can post 280 character messages, this feature did not exist when the Tweet was reported (May 2017) or when the timestamp says it was posted (March 2014)