Where will you do most of your diving? If you will mostly do tropical diving,than a jacket BC with a small amount of lift should be fine. If you will be diving locally in the lakes,consider a wing, with 30 lbs or so of lift, to make sure you will not outgrow the wing and will be able to use a full exposure suit,which will require a bunch of lead.
I'm not sure how you can buy a BC when you don't know how much lift you need. Although, if you purchase a wing with about 30 lbs of lift you should be in the ballpark for cold water diving.
Unfortunately, with jacket BCs, they are also more bouyant, sometimes by a lot, which means they may require even more lead. This may require you to add more lead than your wing can handle, something that is often not taken into consideration when first purchasing a jacket BC.
I didn't realize it at first and when I started diving a drysuit, I realized that my old jacket BC was woefully under capacity, being a small, tropical travel BC. Although, I think my old jacket had also developed some leaks,which was causing even more issues with capacity.
Unfortunately, you can't try out your BC before a class, either. Which means you can't figure out if it will have enough lift for you. With a jacket BC, its still important to make sure you have a balanced rig, if you have integrated weights it needs to be able to float your tank,weights and you on the surface without a problem.
There are calculations that you can do to figure out how much lift you need and how much lead you will need but its more complicated with a jacket BC,because the jacket has a fair amount of inherent bouyancy, which requires lead to sink, as well.
I found my old jacket was sinking if I threw it in the water with just the trim weights and a steel tank. It is fine in the warm water environment and I still use it for pool classes but it won't work for anything else, being unsafe in the ocean with cold water gear.
I recommend waiting until after OW class, then you can try out a rig that you might be interested in with the amount of weights and exposure protection that you will need for the coldest diving that you will do.
It's one thing if you will be diving in the tropics with 4 pounds of weight, a bouyant, AL 80 and a 3 ml, and fully another if you're diving in the local lakes with a drysuit or 7 ml, 24 lbs, a steel tank and all the other cumbersome cold weather gear.
BP/wing is a great rig for beginners, BTW,especially if you plan to dive cold water and/or would like to continue on into any technical specialty like caves or wrecks.
Since it looks like you are from MO, I assume you'll want to dive locally in places like the local lakes. You even have a decent cave, if that interests you, if you decide to get training in cave diving.
I strongly suggest that you make plans to dive locally and regularly from the very beginning. You will be a much better diver if you dive locally and will probably enjoy your vacation dives more by staying proficient locally.
