Technically, to be eligible to apply for the first-time home buyers amount, you would need to be living in the home within a year of purchase. But I would recommend calling the Canada Revenue Agency (CRA), and see if they will let you take the credit, since your home won’t be ready until more than a year has passed.
If you are in Canada or the United States, you can call the CRA at 1-800-959-8281. If you are elsewhere you can call 613-940-8495. This page has more ways to contact the CRA: https://www.canada.ca/en/revenue-agency/corporate/contact-information/telephone-numbers.html
