Is the financing amount possible with our net income?

Hello everyone,

my girlfriend (27) and I (30) are planning to build a house next year.
The planned financing amount is €350,000. (Only house and incidental construction costs)
Now I wanted to know from your experience whether this is realistic.

Income

Me: €2400 net (without Christmas bonus etc.)
Girlfriend: €1900 net (€900 when we have a child)

I calculate with an income of €3300 because a child is expected in 2-3 years.

We currently have no loans, only the usual insurances like disability insurance, pension insurance, household insurance etc. about €400.
Two paid-off cars (2-3 years old) require about 100 liters of fuel per month.
Two building savings contracts where we pay in €200.
Spending behavior is "normal": eating out once or twice a month, holidays about €1500 per year etc.
Current cold rent €730.
Additional costs (including electricity): €200.

Our equity has partly already gone towards the plot of land (€80,000), but this is already in our possession and also already developed.
The plot is relatively flat because a building was already on it before.
Because of the location where we are building, we also save on wastewater charges.

So remaining equity €20,000 (buffer already deducted for kitchen and reserves about €25,000).

For overview
Total project sum (house + plot): €430,000
Equity (incl. plot): €100,000
Loan amount: €330,000

The goal is for the house to be paid off by the time I reach 55 years of age.

Do you see it as realistic to get a loan here? Or the goal to have paid off the house within 25 years?

A 1200 € installment would probably be possible, even if there is not much buffer left. I assume the following: 3300 € - 400 € - 150 € - 200 € - 200 € -1000 € = 1350 € you would have available with a more or less frugal lifestyle. 1200 € at 5.5% (3% repayment) annuity would finance 260 k€ - that would roughly fit with 25 years. At 4.5% (2% repayment) annuity, which you could possibly increase later, you could finance 320 k€ (which would be about yours) and would then be occupied for about 32 years (4.5% over the entire term).