Reply to New Producer setup questions!!

Hi I am just starting to produce filthy electronic music, I have decided which moniters I am grabbing and my only remaining concern is whether or not to get a MIDI keyboard. I am extremely serious about making music and am lookin at getting novation impulse if I do get a MIDI keyboard. Also would 25 keys be sufficient or would 49 make a significant difference? I produce in ableton and I'm starting online courses with Point Blank just as soon as my home studio is set up. Feedback would be greatly appreciated, thank you.