It is not uncommon these days for couples to have children late in life.
- The essence of the sentence is correct, but the reference point is wrong. It is not "couples" that is referred to in the original, it is "some countries around the world". Therefore, your reference point should be a synonym of the same such as "Internationally, couples are..." or "There is a global trend of..." to name a few replacement references for the phrase.
Good work on your direct responses to the questions. These relevant topic references have clearly shown the examiner that you understood the questions, and will be discussing relevant subjects in the reasoning paragraphs. These will definitely help your TA and C&C scores.
Since you are being asked for your personal reference points, then you did a good job in using first person pronouns to clearly indicate your opinion. A general discussion would have worked, without reference to pronouns, but that would have lessened the impact and clarity of your discussion presentation. This way, the presentation remains cohesive based on the fact that you are making it clear that you are the speaker in the presentation.
This is missing a concluding paragraph. The presentation is open ended. The last paragraph is not an appropriate summary conclusion. Rather, it is an expanded discussion of your personal opinion. The essay would have been better had you decided to not write paragraph 3 anymore, since it is only an addendum to the previous paragraph, which already responded to the question. Instead, the current last paragraph appropriately responds to the second question, thus making the essay more cohesive and offering you a chance to write a more applicable reverse paraphrase.