Its best to start trading when the price of bitcoins is low because it will then rise while if you start trading when price is high then it might go down too.
Not certainly, the definition of low and high is trading is base on our evaluation of the current market. We have different interpretation on how the price will rise of course, so if you feel the current price is still has more room to grow then it's always a good timing to buy.
Never doubt your skills and follow others blindly, success does not happen overnight but one thing I can say it choose the best asset which is bitcoin.