I have to agree with both Wade and Steve... Bottle shock is definitely a concern immediately following bottling and so you should try to let your wines sit for a couple of months (mind you, I always open a couple of bottles early to "see how they're evolving") In addition, I'm assuming that a White Zin kit would have been back-sweetened with an F-pack or conditioner. If the sweetener was added immediately prior to bottling and was not adequately mixed, you could get bottle variation.
Also, the same wine can taste remarkably different at different days/times. I don't know how many times I've tasted a wine, even in rather clinical conditions (classroom settings, formal tastings, etc.) and then tasted it later in a different environment (at dinner, at home, in a different glass, etc.) only to have significantly different impressions...
I'd say give it a little more time next batch and try to get to know your wine once it has fully settled down.