Building a house probably refers to marriage and starting a family (see Proverbs 14:1). A young person should not marry before he can look after a family. In (Song of Solomon 2:7; Song of Solomon 3:5; Song of Solomon 8:4), young girls are also warned not to look for love before the time is right.
27 Prepare your work outside; get everything ready for yourself in the field, and after that build your house.