I love my piercings, but you can always take them out if you don't want them anymore. I also love my tattoos, but you can't get those removed(well you can but its a pain). I think they are worth it. Just do your research and make sure you are in complete LOVE with your tattoo and will be in LOVE with it 30 years from now.
It all depends on what you get for a piercing or tattoo. Just think about how you will look when your older. If you get a tattoo get something small and don't cover your entire body. For the piercing don't like gage your ear or anything imagine being an old person with that and your skin won't be as tight anymore and everything won't look Cool anymore and you will just end up looking like one of those old people that everybody tries to avoid. So before you decide on getting a piercing or a tat just think about how it will look in the future.