I love your enthusiasm. I think everyone who takes an interest in wine should take a lesson from you and jump in with both feet! :-)
One of the features about wine.com is they are concerned about weather delays in terms of shipping. Winter is not the best time of year (lol obviously) for wine to sit on truck getting cold, especially red wine. I neglected to mention with a wine shipping service, you should make it a practice to be aware of the weather conditions between where you live and where the wine is being shipped from. I had to learn that lesson the hard way.
As for your selections, great choices! However, you should be aware of the vintages of some of your selections, such as the Nebbiolo, make a dramatic difference. For instance, a 2013 Nebbiolo would be typically considered very "young." In fact, many wine producers will not release their Nebbiolo within a minimum time of four years. So, the 2013 Nebbiolo probably has not had enough time in the bottle to be a good example of the varietal. The dilemma this causes is that Nebbiolo wines tend to be on the more pricey side of the Italian wines. A good bottle of Borolo, for instance, could cost over $100/bottle or more depending on its vintage. I suppose the same could be said for just about every wine varietal. But, the average cost for a good to very good bottle of Borolo will be around $40 - $60 per bottle, again, depending on the vintage.
However, there is funny little thing about wine. Price does not always reflect quality. Some of the best wine I have ever had was under $25/bottle and some of the worst wine I have ever had was upwards of $100/bottle. So, its not a strict "you get what you pay for" scenario. But, like I said previously, if you know the specific years where a wine region had a better than good production, you can gain access some excellent wines from not-so-expensive wine makers operating in the region. For instance, 2010 was a very good year in Piedmonte, Italy, even for the little guy wine makers who sell their wine for a fraction of what the more expensive wine makers sell their wine for. Therefore, you can locate one of these smaller, less expensive wines and get a great bottle of wine very cheap. I found a Borolo made by one of these small guy wine makers on wine.com for a 2010 vintage who was selling the wine for $14.99 per bottle!! $14.99 for a Borolo is unheard of, especially for such a good year! So, I bought two cases. The wine is superb! Obviously, these sorts of gems are not common. But, it is an example of what you can find if you know what to look for. Again, please forgive me for sounding like an advertisement for wine.com, but, that's where I found this hidden gem.
In terms of your white wine selection, Riesling is one of my favorite whites. However, the general rule with white wines is the "younger, the better." I try not to buy any white wine that is more than 3 or 4 years old. White wine typically does not last long in the bottle for various reasons like some reds. So, a 2012 Riesling is likely on the downside of its bottle life and probably not the best representation of the varietal. A good way to illustrate what I am talking about would be to buy an inexpensive Riesling that is no more than 2 years old and compare it the 2012 Riesling. The differences between the two should be noticeable right off.
The same general rule applies to Chardonnay, Pinot Grigio, Sauvignon Blanc etc. But, again, these are only general rules and by no means do they strictly not apply in every case.
Then, there is Pinot Noir. Ahh....Pinot Noir....the spoiled little step child of the wine world. Like a spoiled stepchild, when Pinot Noir is good, its very good. When its bad, it is ohhhhh so bad. Many wine makers consciously choose not to make Pinot Noir because the grapes are incredibly temperamental and notoriously difficult to work with. However, when the gods, the planets and the stars align just right, there is no wine on this earth than can match the flavor of a good Pinot Noir. However, the true beauty of Pinot Noir lives in the fact that it is so difficult to make. The level of care and skill that goes into making a good Pinot Noir is one of the reasons I like it so much. A good Pinot Noir is truly a work of art.
Pinot Noir is one of the few reds that follows the same general 3-4 year rule that applies to white wines that I described above. Pinot does not last long in the bottle either. At most, maybe 6-8 years under ideal conditions. As such, try to look for a Pinot Noir that is no more than three years old. A great Pinot Noir for under $20 is Shug 2013 Sonoma Coast Pinot Noir. Make sure its the Sonoma Coast and not Carneros. If you can't find the 2013 Sonoma Coast vintage, 2014 is excellent as well and is also under $20.
You can find a chart on line with a simple google search that shows each wine region and the ratings for each production year.
If you have any questions, let me know. I would be happy to answer them. If you run into a wine that you particularly liked, let me know as well. I'm always on the lookout for a good wine. :-)