You’re overthinking. It’s really not that big of a deal.
However…you can wear an actual pad instead of just thin panty liners for extra protection to make you feel more secure. For your tampon, I suggest you use size Super Absorbency or Super Plus if you have problems with bleed through. Change it right before you start making out with him. If you’re bleeding through a pad AND your tampon within 4 hours, then you might want to discuss this with your doctor. ‘Cause that’s not typical.