I booked a tanning session for a 'base tan.' How do I cancel without making it a group argument?

Three of us booked tanning sessions before a holiday. I paid a £15 deposit because my friend said a base tan would stop us burning at the beach.

Then I read [NHS advice that a tan does not protect skin from the sun's harmful effects and that there is no safe way to get a tan](https://www.nhs.uk/live-well/seasonal-health/sunscreen-and-sun-safety/). I want to cancel my session and plan sun protection for the trip.

My friend says I am making her look irresponsible after agreeing to go. I did agree. I also repeated her explanation to our other friend, so I am part of how this became the plan.

How would you correct what you said without turning the cancellation into a lecture about everybody else's choice? Losing the deposit would annoy me, but using the session simply because I helped organise it would be a strange way to put that right.