Well, but things that definitely make life nicer. I find the question justified: why build now, necessarily? Is there a good reason for that? If not, keep saving, increase your equity, stay on it, maybe you’ll come across a nice plot of land, then you can buy it with your equity, keep saving, and build sometime later.
The family situation is still open, so it’s not like two children don’t have rooms now and you absolutely have to expand, but it’s up in the air whether there will even be a viable partnership and if there will be children at all.
Of course you can still build then – and if you have the money, definitely so that everything is possible in the future. But if money is tight, I would wait and see what I really need. If I stay single, 150sqm is ample – but only if I haven’t wasted 30sqm on two (then unused) children’s rooms.
Even as DINKs, you’ll build differently than if you have children – and as DINKs the financial situation should also be friendlier.
I would now continue to inform myself, stay on it, look around, accumulate knowledge, visit fairs, look at model parks, and – save.
Maybe find a nice plot and first buy that.
In the past I would have said: well, just take out a building savings contract and save on that. Given today's financial situation, other investment forms are wiser. You can also get smart and invest your money accordingly. Always with the thought in mind: if I build, I have to be able to access it.
So to be clear: I am not against someone building their dream house as a single, but does it really make sense to have to give up many features you’d like and build a house that you don’t yet really know how you ultimately need?
I started planning our house in my late 40s. It was clear then: children would no longer come and the partnership was stable.
I had always wanted to build a house, but the situation wasn’t right for it. Meanwhile I have increased my equity well and we were able to start with a comfortable equity share.
And now we have a house tailored exactly to our needs. Fits! A classic single-family house with two children’s rooms would have been a misplan for us.
That’s certainly not the royal road for everyone, but it was mine. After having avoided a steady partnership for years and thus not having taken the classic partner-family-house-building path, that was fine.
So to the OP: nothing is running away from you, you’re not under pressure (because kids need to be accommodated), you already have solid equity (just under 100,000, right?) and you don’t need to rush anything now.
Then let good things take their time!