@jonblack
It sounds like you have a healthy outlook, that of renting equipment until you have opportunities to dive more frequently and gain more experience. There’s nothing wrong with renting your gear for a few seasons until you develop an idea of what type of diving you and your son are drawn to and the equipment that will best meet your needs and budget. “Buy nice or buy twice” is a good rule of thumb but it makes the assumption one has a mature grasp on his needs and preferences. I bought nice but still bought twice because my needs evolved.
I concur with others that getting a properly-fitting mask is critical. After all, yours and your son’s ability to see the underwater world without nagging leaks are one of the most important things that will ensure you two can share in the enthusiasm.
I also concur with others that an air-integrated computer is a bit superfluous right now. I think it’s important to first develop basic dive skills (monitoring one’s gas and communication). Would you be as good a driver today if you had started with all the driver aids now available on cars?
I’m a bit out of touch with the available options for a recreational computer that interfaces with an online log. I do think a DC would be a great purchase for your budding marine biologist. I encourage you to go simple/economical. As much as we think we know our teenagers, they can take unexpected turns off the path.
Some great news - you live in Georgia next door to Florida, the world’s diving capitol. There are tons and tons of opportunities to get linked up with marine biology labs such as Mote Marine Laboratory, university and other institutional marine biology programs and regular dive charters that either host or support healthy reef and coast activities.
Have fun with all of it and let us know how you guys get along.