CONGRATULATIONS, JMJ! What wonderful news!
Well, another way to look at it is that the Mass is meant to be a celebration. Certainly, a proper reverence is expected during the Liturgy of the Eucharist; however, JMJ makes some excellent points below. The Gloria and the Gospel Proclamation are songs of praise, and clapping is not inappropriate within that context. Same goes for the recessional, save for the more somber season of Lent.
I reference again the great King David, who wrote certain Psalms specifically for the purpose of praise & the inclusion of clapping and dancing. He worshipped with great passion, joy, and reverence.
As to clapping during the Gloria, does anyone know if there have been any specific prohibitions or any other information on the topic. While the Holy Sacrifice of the Mass is something to be very serious about, the Gloria is a song of praise. It is taken out completely during Lent and brought back with great rejoicing at Easter. If clapping during Mass was ever appropriate, I think it would be during the Gloria.
Of course, I seek obedience to the Magisterium. Is the Gloria not ever a place for this kind of praise? Forgive me, I am still learning. Proper liturgy is not something that was really emphasized in any of my churches growing up. I do not even know all the abuses going on, but as I learn the 'why' behind the way everything is, I fall more and more in love with the beauty of my Church.
Though some may deem it inappropriate, I have yet to see any official liturgical document declaring that clapping during the Gloria (or during Mass at all, for that matter) is expressly forbidden.