Hi Cevat, the sentence is not correct. In the context of your sentence, the correct grammar is:
Now we are following each other on Instagram
The answer from GuideDogSaint李凯森 can be correct too, where you can put "now" in the last part. But in your sentence I think it's better to put "now" in the beginning, because you want to emphasize the timing, which is "now". So we're not emphasizing the action (following each other), but the timing of the event. Hope it helps!