Am I bananas?

I put a booking deposit on a three-bed in a town on the commuter belt. It’s a terraced house and a new build. It’s on at 405k with a scheduled completion date for towards the end of the year.

I would putting up a deposit of around 100k and using the HTB.

I expect to pay a mortgage of between €800-€1200pm. I would rent a room and try to pay down the principle as quickly as possible.

My plan would be to live in the house for around 5-10 years and then trade up or possibly keep the house as a rental property.

My question for you folks is, is this bananas? 405k seems like quite a lot. I am also anxious that it’s a terraced house that it’s possibly over valued. However, the plans look great. There’s no show house in the development but of what’s been built it looks very promising.

I think it could be a really good match and the location is perfect for me for a variety of reasons but I’m just quite anxious about it.

Any perspective would be greatly appreciated.