I don't usually swear. This is not to say I won't. Certain people, certain situations, just make it so easy
In a sacred setting, I do not swear. Mind, I have been known to cry, "SH**!!!!! if I drop anything burning, or my charcoal block does something funky. O_O Those things are unpredictable!!!! I'd play with candles for hours as a young-in, and I am very safe with fire, because I play with it so much. (Heh heh... sounds strange reading that part aloud O_O) But charcoal blocks are the only things that make me nervous!!
Anyway, I think swearing can be OK. I choose not to because it is another way to show respect with the powerful beings that are choosing to share their space with me, who have come to lend their talents.
Another thing I really want to address:
Would the God and Goddess punish me?
Many people after converting still carry old beliefs. Who here has not carried over the guilt, the embarrassment, the fear that drove us away from them? Many of us are successful in ridding ourselves of this, but it takes a long while after a lifetime of conditioning.
Don't feel like if you do something wrong, you will be punished. You seem like a very good person, high morals and a sincere desire to be good in the eyes of the Divine and to your fellow human beings. You are a good person. If you slip up, if you mispronounce a god's name, if you trip over something in your circle and scatter a sacred offering across the floor, DON'T WORRY. Laugh ^_^ If you feel bad, say sorry, but ENJOY your practice ^_^Don't be afraid that something bad will happen if you make a mistake. Life is about mistakes! If we were born perfect, we wouldn't have interesting lives. Because we are not perfect, we are expected to make mistakes, encouraged.
I really was plagued with guilt, fear, and an outright timid nature when I first started, and even up to recently. The Divine wanted something, I did it. If I stepped on a plant in the woods, I'd feel VERY badly and say sorry a million times. Then my Guides and all these power animals started harrassing me. "WE HAVE TO TEACH YOU THIS NOW!" "SPEND TIME WITH
ME!" And I realized this was a lesson. They were teaching me not to be a doormat. I am very grateful to them. Now, I walk in the woods, and I step on a plant, and I still feel badly for a moment, say my sorry, but I do not let it consume me.

Do you understand what I am trying to say?? Im sorry if this does not make sense.