When you trade BTC you're indirectly investing in BTC, but investing can be in many form.
It's always better to understand in what you're spending on. Money isn't the only one, you're burning time which also burn your opportunity cost.
A. Feel
You could try some airdrops given for free, there's plenty of it - enough to get a feel how wallet, storing and distribution works.
Or you could decide to spare $100 and play around with it. It has to be a value you did not mind LOSING.
B. Learn
You could search for 'blockchain' and 'cryptocurrency' to learn at first.
Then find your preferred coin again, to study how it actually works.
When you take either A or B is satisfying, you may proceed to trade (assuming you understand trading) or the simplest investment; buy&hold.
It's always better to understand in what you're spending on. Money isn't the only one, you're burning time which also burn your opportunity cost.
A. Feel
You could try some airdrops given for free, there's plenty of it - enough to get a feel how wallet, storing and distribution works.
Or you could decide to spare $100 and play around with it. It has to be a value you did not mind LOSING.
B. Learn
You could search for 'blockchain' and 'cryptocurrency' to learn at first.
Then find your preferred coin again, to study how it actually works.
When you take either A or B is satisfying, you may proceed to trade (assuming you understand trading) or the simplest investment; buy&hold.