Don't propose on my birthday, don't propose on my graduation day, don't propose on Valentine's Day, don't propose at someone else's wedding...
Keep the proposal date a separate special day not be shared with other holidays/milestones
If my date asked me to get tested before we had sex, I wouldn't be offended. I'd be very impressed. To me, asking someone to get tested doesn't suggest you have a negative opinion of them. It indicates that you're sensible, cautious and proactive about sexual health.
Yo nunca fui de Papá Noel. Siempre fui de cartas al Niño Dios. Mi abuelita se inventó que el Niño Dios olía a rosas, así que a la media noche, sin que los niños nos diéramos cuenta, ponía ambientador con ese aroma en los cuartos. A mí se me salía el corazón de la emoción.