Recommendation is 500 size to start.
450L is a small aircraft and very fast, the power level of 6S is too strong for 450 Body, 3S power will be better. It flew almost simple 3D later had to change.
Although 500 is big in size and maintenance is expensive, but the 3D action can be completed.
What’s more, no matter what you are into the aircraft, the aircraft’s price is decimal, even if you buy the 700 level, too. The most expensive is the batteries, chargers and power supply.
For the very beginner, super combo will be better, such as for Trex helicopter, you may choose the combo excluded 3GX, then buy vbar and gyro after getting the heli, you can simulate the heli when you do the assembling.
Meanwhile the beginner need to be familiar with the heli structure, later when you ask the problem, you have to know which parts is what others say.