Better now than later, and better late than never.
I would say, if you are concerned about hitting the market on a high note, diversify a portion in to Bonds, or something that might stay afloat if a crash comes along. On that note, even if a crash does come, if it hits in the early years, you will be happy to be buying up at firesale prices. If it hits 5 years down the road, your investments will already have appreciated 40% and the "crash" will be a blip on the radar for you to weather through.
In all cases, the more you put in now, the better your chances of having more in the future, just don't get scared and pull out early, and you will be just fine. Also, that's enough money to do a lot of things that might save you more money. So consider if there are any other things you can use that money toward besides market investing, such as debts, loans, family security, house by work, a bicycle, a home garden, otherwise best of luck.