Realistically, you will probably generate about 12,000 kWh annually with your system. Without storage, you will consume 4,000 kWh yourself. 8,000 kWh will be fed into the grid.
With an appropriate storage system, you might be able to consume 7,000 kWh yourself.
Therefore, I would build the system smaller and add a storage system. The talk about falling electricity prices is complete nonsense. In the last 40 years, electricity prices have never fallen and they will not fall in the next 40 years either.
You just have to look at fuel prices. Oil price keeps falling, fuel price stays high. Exchange electricity price falls dramatically, nevertheless widespread electricity price increases between 50 and 100 percent. Thanks to the electricity price brake.
With a Renewable Energy Act remuneration of 7.5 cents, there is no point in starting with a small photovoltaic system either. Even if you fed in fully and received 8 cents, you could expect 960 in feed-in remuneration. Your electricity bill would still be 3,200 euros for your 8,000 kWh consumption, minus the feed-in remuneration and including the electricity price brake. However, it will expire again in April 2024.
We could also be at 60 cents per kWh by then.
A cost-benefit calculation would be ideal with a 10 kWp system with a 15 kW storage.
And expect zero yield in January and December. Nothing comes then, but you also have to heat the most during that time.