I'm building a desk out of birch plywood. I had planned on painting it the same color as the trim and bookcases in my office. (I have leftover latex paint from that recent project.) I was thinking I should seal it with polyurethane so it would hold up if the kids set a wet glass or something on it, but as I was researching that I've started to second guess if that's the best plan. Thoughts/advice for a newbie? Thanks in advance.