It takes years to build good credit
You’ll need at least 24 months of consistent, on-time payment history to get your credit score to an acceptable (average) level.
Adding your wife as an authorized user on your credit card will build her credit score. It’s called Credit Piggybacking, and it’s a fairly common practice. Make sure you both use the card for regular purchases, wait for the statement and pay it in full every month. That will build good credit while avoiding interest.
Be advised that credit score account for only small part of the lending decision. Lenders will look at your actual credit reports, will probably considered them to be thin and will take extra care approving you on a mortgage. Especially your wife – her sole item on her credit report being your credit card.
During that time, get a book called “How to Buy your First Home”, or “Buying a Home for Dummies” and get yourself educated on the subject. Best $20 you will ever spend your whole life.