Planning for and eventually getting chickens is an exciting endeavor! First look into local ordinances, as they may outline or restrict how many chickens you can have in your location or on your size lot. Also consider your budget (or if you even have one) for coop construction/purchase and how much space your chickens will need. Both of these factors may impact your flock size.
Others have mentioned to consider starting smaller. One of the benefits to this is that you can add birds in pairs for a few years until you build up your flock. Now the age of your birds is staggered and as the first birds get older and start to decline in egg production, you will still have some that are a bit younger and at their peak. If you aren't maxed out on birds, down the line you might have the option of letting your chickens hatch some babies of their own and growing your flock that way. There are so many possibilities!
You could also visit a local feed store that sells chicks and see what breeds they typically carry and then start researching those breeds to see which sound like the best fit for you. I know my local feed store only purchases breeds that tend to do well in our climate, so it's nice to have someone to narrow down the options.