There are some circumstances under which a person really shouldn't get tattooed—at least not yet. If you find any of the things on this list are concerns, you might want to wait.
You're Not Old Enough to Get One Legally
If you're not old enough to walk into a professional shop and get a tattoo legally, and your parent/guardian won't (or can't) give consent so you can have it done legally, then your only option is to get it done by some scratcher or do it yourself. This has become particularly common as tattoo guns are more easily purchased online. Still, both methods of tattooing could lead to serious infection or disease—and the tattoo you get is certainly not going to be worth it.
You Don't Have Enough Money
If the tattoo you want costs twice the amount of money you have, don't just go get a cheaper tattoo. Too often, people change up their artist just to find someone who will do it cheaper, and the results end up very bad. If you want a tiny flash tattoo, that's one thing. But if you want a large, detailed piece, wait and save up. When it comes to body art, you shouldn't be looking for a bargain.
You're Not 100% Decided on the Design
If you're not absolutely sure about the tattoo design you want to get—or if you've only been absolutely sure for a couple of days after changing your mind several times before—you're really not ready to get that specific tattoo yet. Let it marinate, and think about whether you want that design on your skin for the rest of your life. Otherwise, there's a large chance that you'll end up regretting it later on.
You Don't Understand the Language or Symbolism of Your Chosen Design
The symbols may look pretty, but there are websites dedicated toward making fun of people who got tattooed in a foreign language they couldn't read because the translation was clearly not what the person was going for. It very notably happened to Ariana Grande, so if you think you're above it and going to a more professional artist—don't. It happens all the time; don't let it happen to you.
It also brings up issues regarding cultural appropriation if you intend on getting tattoos with symbols close to a culture you have no affiliation with. There's no reason for it, particularly in instances of religious symbols. Learn the difference between appreciation and appropriation prior to getting something permanently on your body.
You Lost a Bet, or You're Being Pressured Into It
Getting a tattoo is a pretty big decision for most people, and shouldn't be the result of peer pressure. Don't make any bets that end with someone getting a tattoo, and don't let anyone pressure or force you into getting something you don't want. It's your body, your life, and you're the one that has to live with it and see it every day.
This goes for relationship and friendship tattoos, too. While most don't last, a tattoo definitely will, and anyone worth having in your life won't pressure you into getting a tattoo you're not comfortable with.
You're Thinking You Can Just Have It Removed Later
If you're thinking this, it seems like you might already subconsciously regret your tattoo. Getting a tattoo with the mindset that you can just have it removed if you decide you don't like it later, is kind of like getting married with the mindset that you'll just divorce if you're not feeling it. If you're not in it for the long haul, or you're on the fence, don't commit to something.
You Want the Name of Someone You're in a Relationship With
Name tattoos are a risky choice, particularly when it's someone you're involved with. Relationships end, and if it does, you're still stuck with a permanent reminder of a failed coupling. You'll have to get it covered up, or maybe even removed. If you're not completely committed and in a long-lasting relationship, a name tattoo is a very bad idea.
You Have Health Issues That Could Interfere With Your Ability to Heal
Some health problems could cause serious problems during the healing process of a tattoo. Diabetes, heart problems, and circulation issues are just a few that could make getting a simple tattoo very dangerous.
The same goes for medications that thin the blood, and/or ones that could interfere with the successful implantation of pigment. It's also possible to have an allergy to tattoo ink, so if you think that might be possible, it's best to talk to an artist before putting needle to skin.
You're Not Sober
You can't legally get tattooed while under the influence of drugs and/or alcohol, but it's in your best interests to be sober anyway. Yes, people make stupid decisions when inebriated, but that's not even the worst reason. Alcohol thins the blood, which would make for a messy tattoo that'd have a hard time healing. All in all, it's not a recipe for success.
It's an Unclean or Unsafe Environment (Party or Outdoor Event)
Getting tattooed at a party or during a fun event may seem exciting, but it's usually just a recipe for disaster. It's rarely sanitary—even if it "seems clean," there are sanitation procedures required at professional tattoo studios.
The same procedures aren't required at your friend's place. If you have no idea who the artist is, what their qualifications are, how clean they are or what outside elements you might be exposed to, it's a terrible idea. Temporary, fly-by-night tattooers who are here one day and gone the next have no responsibility for their clients' safety or the outcome of their tattoos. It's best to go to someone you know and trust.