To be honest, no one can accurately determine whether it's "early" or "late" — that's essentially predicting the price, which no one can do. Bitcoin can be bought at any time, and you can even buy fractions of it. The issue is never "is it too late," but whether you understand the risks and whether you're only using money you can afford to lose.
Instead of agonizing over timing, a more practical approach is Dollar-Cost Averaging (buying in batches) to lower your average cost, avoiding buying all at a peak and also avoiding missing out on lows due to fear. Combined with position management and stop-loss, this is more realistic than "catching the bottom." For the cyclical logic, see Bull and Bear Markets and Cycles.
The above content is for educational reference only and does not constitute investment advice.