First of all, congratulations on your new bike!!

Many road bikes made today don't even have the option of coming with a triple because the extra weight slows the bike down. Having said that, if you need a triple for climbing, it is totally worth any extra weight.

I went from a triple to compact double on my road bike and haven't missed the triple at all. It isn't mountainous around here, but plenty of rolling hills. It certainly hasn't slowed me down.

I can't speak personally to the tires, but a quick google search came up with this which indiicates that the tires are not going to slow you down either:

"Finally, there’s the question of the speed value of 700c versus 650c. There will always be exponents of one wheel size versus the other. My training partner slays everyone on straight-line descents, even those who weigh considerably more than him, and he swears it’s his 650c wheels. Others claim differently. One cannot deny, however, than many of the very fastest bike rides in the history of timed triathlon racing occurred on 650c wheels, both in the men’s and women’s fields. All this is anecdotal, however rides in Zofingen, IM Canada, IM New Zealand, IM Hawaii, IM Germany—most of the big courses in the big races of yesteryear, when 650c wheels were popular—still stand up today, as much as 12 and 15 years after they were accomplished."

Now, the bigger question is who on earth are these people who are trying to bring you down about your new bike?? As long as you are comfortable riding it, DO NOT LISTEN TO THEM! There is always someone with a different opinion about what is faster. You have your nice new bike now. Have fun with it and don't second guess yourself! Have you posted a picture yet?