i would usually try. but my opponent always gets to riled up and throws a punch. im just worried i wont be able to use aikido im only yellow belt but i got my orange belt grading in 3 months. and i want to be able to have the mind state to use it when the need arrives
unless you are already
strong and fast (fit with contact conditioning from "street" or gym), no martial art will gets you prepared.
My guess is that something like three to ten plus years (or never, if your instruction and practice isn't "honest" and sustained enough) of training and fitness
might get someone feeling prepared to respond to unarmed aggression and I'd imagine Aikido would take longer since a more forceful responses (reverse punch to face or side stomp kicks to knee, etc) are not considered.
Most often the Aikido (or Karate or Jujitsu or kickboxing) art works fine, but that yours may not.