Does this make sense?

Because I will soon be working in the FSJ and I want to earn money from the money…

an iPhone (probably then…) 13 Pro Max with 512GB (until now only had a 7+)

Airpods Pro

Xbox Series X and Playstation 5

buy a gaming PC

That is clearly your decision.

Your money, your decision

But you don't earn that much in the FSJ to buy everything straight away, you only had 440 euro yourself and some acquaintances in the FSJ can only earn 300 euro

3600 euro for the whole year ergo 300 euro per month

It is still tight for everything, especially if you don't want to / can't hit mom and dad for everything else

I recommend learning how to manage money early. Spending it right away is of course a possibility. But you can also learn an effective method of saving right from the start. One is the three-account model.
The following question is completely different from yours, but my advice remains the same:

There are people with a five- or six-figure monthly income who owe a debt to the bank. You never learned how to handle money.

How do you mean? Iphone ~ 1500 euro xbox / ps 998 euro airpods ~ 250 euro gaming pc ~ 850 euro

Well at 6000 euro you can easily spend 4000 euro a month

I would save 4,000 euro to get to the levels of financial protection and financial security as soon as possible. You can then take a little more time for financial freedom

It all depends on how you make a living. In other words, everyday things like eating, keeping the laundry, living, heating, electricity, …

It makes a huge difference whether you can put your legs further under Mum's table or whether you have to take care of your own living. It also depends on whether you can count on a "subsidy" from your parents if you have financial problems.

And last but not least the question is what future expectations you have of your own salary.

Or should I save the money like my grandma says?

You will have to do that first because not all of the first salary will have to be paid. A small reserve is of course not bad either. Usually this is said to be 2 months' salary.

The money is no longer created by dividing it into different accounts. We strongly advise against having multiple checking accounts for one person. Multiple accounts are only useful if there are more than one person.

Well, at 17 I don't have to pay anything at all.

That's not right and I haven't written anything from three checking accounts either. For example, I have a call money account (with its own account number) that is linked to my current account. So that's two accounts at the same cost as the giro alone. You can also set up 3 sub-accounts at other banks.

Money increases because you earn more than you spend and that you invest intelligently. This becomes easier, among other things, if you don't have saved money in the account on which the daily expenses are managed. If you've set up a savings plan, what you've saved has to go somewhere. So in a savings account. It doesn't have to be the classic savings account.

The three-account model (not the three-current account model) helps those who can't manage their money and who need a structure. There are people who are very structured when it comes to money. But they don't have all their assets in one account either.

The following may apply to some people, but the general rule is that you don't throw your entire wardrobe - including your shoes - in a closet unsorted. The closet has compartments. If you don't use them, you usually don't have anything clean to wear, although you may have a lot of clothes.

I think this comparison shows what I mean.