It depends why are you buying. Buying for a long-term hold or buying for a trade. If you are buying for long-term, jump in - long-term things are very bullish in my opinion.
If you are buying as a trade, you should wait for a good signal, at the moment i don't see to many signals to support a buy. We are below all moving averages, broke support at 10,800 , broke support at 10,300, testing constantly the 10k area. Also looking at BTC on different timeframes, weekly, monthly really shows a lot. I did just that in my latest article, you can check it HERE if interested.
Why do you think it is a buying opportunity ?
I think we're seeing the combination of good trade and good investing right now. There's nothing more rewarding when investing long term than a great entry!
Yes, good entey poimt is half a trade :)