I'll forgo a review of your report at this point. Due to your obvious confusion and questions, it will be better to clarify things for you first.
what kind of data should I compare
There are no set formats for data comparison. Report upon the available information in the way you would be most comfortable doing so. Even during an actual test, should 2 or more students receive the same image, their reporting style /formats will vary due to different analysis approaches.
should I describe the similar trend between the two genders?
Yes. Report on the trends separately. One sentence, or 2 for each gender depending upon what tend you want to present ( high, Iow, or high AND low).
to link the datas from the graph in 20 minutes?
Do not write in compressed sentences. Always have a topic/anchor sentence at the start. Then follow-up with individual comparison data based on the graph. One idea per sentence. As long as you write at least 3 sentences, you will be sure to meet the minimum word requirement.
For this image, I would have done the comparison on a per gender basis to make it easier to develop the paragraphs. One for men and one for women. I would have done a joint gender based comparison only for the trending statement.
I hope I was able to clarify your questions. Then try writing a new task 1 essay using my advice. Let's see how you will do. feel free to ask new questions in the new thread.