Week 5 a single bud looks ready?

Should I cut and begin to treat a bud thats ready on a plant, it's only like a 3g bud compared to a rough guess of the rest of the plants 30g body, would taking this ripe bud have any ill effects? The bud is for sure amber and I just got a microscope in and all the trichomes are developed on it.

Would leaving that bud make it over-ripe and begin to degrade the THC content if I wait to do the whole plant at once?

According to my Jorge Cervantes Grow Bible, it's perfectly okay to harvest some parts of the plant before others... typically the lower areas. Some growers even purposely stress their plants towards the end of flowering in an attempt to get some swelling buds. Don't give the plant a home extreme makeover, but feel free to start indulging on you reward.