I started to pay close attention to BTC 3 weeks ago and its price was about $7000. And up to now its price was $12500, reaching it's peak. Is it appropriate to invest in bitcoins from now on?

Abytime is an appropriate time to buy bitcoin that is what i always say. Whenevr they say that it might too late I would come back to them with a line that at least you went on and climbed the rope tather than never and lived with the regret