As always:
Computers will always be faster and/or cheaper and/or smaller and/or have more capabilities in the future. Whatever you buy will be out-of-date sometime. This is known.
That said, wait until you just gotta have one, and, if what you can get suits your needs and had a price you consider to be reasonable, buy it and don't look back. Stay away from Apple's site and from ads for a while. Assume that the day after you buy it they'll drop the price and/or upgrade it and/or replace it. Just enjoy your new purchase. My older Macs are as fun, in most ways, as my newest one, and my newest one is now almost 10 months old.