How much knowledge about Bitcoin do i need before i start investing.
You will be able to tell because you will be very confident in your investment enough not to panic sell during dips and dumps. 
I want price of Bitcoin to reduce so i can start my investment, anyone knows when the price of Bitcoin will fall so i can begin.
Feel free to buy less Bitcoin for the same amount of fiat later. 
I did not take my opportunity when i was introduced to Bitcoin and this forum, what should be done to correct my mistakes or am i late?
You can learn more about Bitcoin on this forum. Read the pinned topics beginners & help board. to get started.Welcome to Bitcointalk.