Young couple (student and engineer) want to build

Hello,
I (29, employed for 2.5 years as an electrical engineer) and you (26, student of teaching, shortly before the first state exam) want to build in BW. Currently, we are not married yet. The house and financing are in my name and no prenuptial agreement is planned (normal gain adjustment). Wedding is coming soon but already paid for.

Financial situation:
Equity 200,000€

Monthly net income (only me) 3200 + 13th salary and a bonus payment of 700€ net (igmetall)

The car is relatively new, so hardly any repairs are expected.

Currently, we pay no rent (apartment at my parents’ place)

House costs:
550,000 from the developer (140 sqm) plus own work KNX, floor without tiles (100 sqm), doors (6)

The house only meets the energy saving ordinance standard, so no KfW financing.

Financing amount:
I would like to finance 410,000 with a monthly rate of 1300€ and at least 3000€ annual special repayment. What do you think, is that feasible?

No. 410 is too much for 3200 net. I think rather a max of 300 is appropriate.

Forgot to add, after the wedding it’s about €3700 net and a reclassification is also upcoming. So about €3800... These amounts already have the company meals deducted (100€ per month) but now it’s bargaining down to the last cent, still this should be taken into account.

How is it planned once your girlfriend earns money? Do you just put everything into one pot and pay everything from that, so you both are listed in the land register, or is everything supposed to be under your name and she pays rent or something like that?

Forgot to add, after the wedding it's about €3700 net and a reclassification is also due. So about €3800... The company meal (100€ per month) is already deducted in these amounts but now it's negotiating over the last cent, still it should be taken into account.

Only as long as she doesn't earn any money After that it's €3200 again. Tax class 4 is like 1

We put everything into one pot; through [Zugewinnausgleich] she is secured. The equity comes from me.