In short trading? No its not the best time to buy bitcoin on its peak price or hyped price knowing that the cause of such increase because on the upcoming bitcoin gold event but if you do buy bitcoins for the sake of free bitcoin gold then its still possible but would be somehow risky if you wont able to get out on the high price because I do really have a doubt that the price will surely dip again once bitcoin gold have been accumulated by its users but if we do talk for long term then anytime would be a best buy considering price is still young.