Does aerobic exercise really help to improve brain health?

I have been doing daily jogging a month ago, started from 1.2km for 10 minutes to jogging 5km within 30 minutes now. But I have not yet noticed any brain health improvement at all: my reading speed still makes me embarrassed all the time in the class, when my peers have already started writing I have only read less than 1/4 through the article, my friend gets the assignments done way faster than I am, I keep dying for the same silly mistakes which are completely avoidable when playing games. All of those make me wonder that if aerobic exercise really is that good for our brain while I have been bombarding all the time by the messages the experts are saying both online and in real life along with their countless scientific evidences to prove that why and how aerobic exercise is an "one of the most effective and powerful way to improve our brain health". Of course I am not naive and silly enough to expecting to be Albert Einstein after exercising the very first day but I do want to see some very minor changes in my brain function after 5 weeks workout, its not easy and sometimes I need to forced myself really hard to go out and run for 30 minutes and I want my efforts to be meaningful and I want something good in return.

 

No idea unfortunately