Picking individual stocks often seems like the right start:

Found a strong company - bought it - made money.

The problem is that at the beginning of the journey, this almost always turns into guessing.
In this sense, an index is a more rational foundation.

Why it makes sense to make an index the core of your portfolio:
1. It removes the risk of making mistakes at the start
A beginner errs not in choosing the market, but in choosing specific companies.
An index automatically spreads that risk.

2. It provides market returns without unnecessary decisions
You don't have to constantly answer questions like:
-what to buy
-what to sell
-what to replace it with
This reduces the number of mistakes and emotional actions.

3. It creates a foundation
An index is the "framework" of a portfolio that grows with the market and doesn't require constant intervention.
But that doesn't mean individual stocks have no place.

When stocks become appropriate:
-when you understand the risks
-when you have a time horizon of several years
-when you are prepared for drawdowns in individual positions
-when you have a strategy, not just a desire to "catch growth"

In this case, stocks are not a replacement for the index, but an addition on top of it. Starting your journey with individual stocks is like building a house from the roof.
An index is the foundation.
Stocks are the next level, once the foundation is in place.
Investing is not a choice between "index or stocks."
It's a matter of sequence and maturity of approach.

"Building on the infrastructure of today, investing in the breakthroughs of tomorrow"