Hi @GhostlyFigure02,
My own concerns about young earth creationism are not around the age of the earth itself, but about what gets presented as evidence for it. Science is a subject that needs to be approached in an honest and responsible manner and shouldn’t be treated lightly, because if you start approaching one area of science in a sloppy, dishonest or conspiratorial manner, people will start approaching other areas of science in a sloppy, dishonest or conspiratorial manner as well, and in some cases that can put people’s lives in danger. We’ve seen that a lot with covid-19, where hostility to masks and vaccines has ended up killing a lot of people unnecessarily. YECs seem to be particularly predisposed to believing conspiracy theories about such matters.
The Bible verse that I quote in particular in this regard is Deuteronomy 25:13-16:
¹³Do not have two differing weights in your bag — one heavy, one light. ¹⁴Do not have two differing measures in your house — one large, one small. ¹⁵You must have accurate and honest weights and measures, so that you may live long in the land the Lᴏʀᴅ your God is giving you. ¹⁶For the Lᴏʀᴅ your God detests anyone who does these things, anyone who deals dishonestly.
What this basically means is that when discussing science, there are rules to be followed and standards to be maintained. (Basically, mathematics and measurement). Any creation model, any interpretation of Genesis 1, any challenge to the scientific consensus on the age of the earth or evolution needs to obey these rules, otherwise it isn’t honest.
The point I would make to your pastor is that even if scientists have got it all wrong, and even if the earth really is six thousand years old after all, the Internet is awash with arguments to that effect that fall so far short of these rules and standards that they are an outright mockery. Anyone taking a stand on such issues needs to make sure that they know what they are talking about and that they understand the subject matter sufficiently to be able to filter out the bad arguments from the good ones, because otherwise they aren’t going to be upholding the Bible; instead, they will be undermining it. It’s also far too easy for well meaning but badly informed Christians to charge into the debate with all guns blazing only to find themselves quickly getting waaaaaaaaaaaaaaaay out of their depth.
So rather than saying that the earth is x years old or that y evolved from z, get over it, just caution people that they need to know what they are talking about before trying to tackle complex technical subjects such as these. Are there any good arguments for a young earth, your pastor may ask? So far, I am yet to see one.