As with any investment, there is always a little bit of a risk. If you are looking to make money in the long term (at least a few years), it does not matter if you invest when Bitcoin is at 1100 or perhaps 1150. I believe that the price will naturally increase rapidly. However, if you are thinking short term, now is probably not the right time since Bitcoin is close to an all time high (so very risky if you are investing short term).
It still matters since it's your starting point. Supposed that you bought at $1100, and exactly ten years from now, you're going to sell your coins and at that time, the price was just $1200. That's just $100 profit for every coin and $10 profit for each year. It's 1% gain per year.
The price might increase rapidly, but what really matters is the time that you're going to sell your coins and the time that you bought them. Whatever happens in between is irrelevant since you didn't sell at those times. This is why you should always check out the latest news to whatever coin you invested in. Like I said, supposed that you invested at $1100, and after ten years the price was just $1200. If you checked the news more, then maybe you were able to sell at a much higher price in between the time you bought your coins and the time that you planned to sell them.