Okay, I have to weigh-in on this post. As you can guess from my name, I am heavily tattooed. I wear a suit to work and even if not required by policy, I would to cover my artwork. (Sometimes, you still can catch a glimpse of my calf piece if I cross my legs when I sit down.) I love all my tats and have no regrets about any of them. They all have meaning and were done by a great artist. I am all for people having tattoos.... if they really are sure it's what they want.
Alot of people see my ink and say "Oh that's cool. I want to get (fill in the blank) on my (fill in the blank)." My response is you better be real sure. There is a social stigma to it. Especially with large pieces.
People associate them with lower class, although good tattoo work is anything but cheap. My FULL backpiece (from collar to belt) alone took around 50ish hours and a couple years to complete. Cost would be around $8000 dollars. For anyone saying that's too much for a tattoo. You're wrong. This is something that you will have forever. It is the same mentality as never paying more than $350 for gun that may save your life. People also associate being heavily tattooed with being a criminal because of the popularity of gang and prison tattooing. However, anyone who bothers to look can usually see the difference quickly.
In terms of work and jobs, I can tell you visible tattoos are still not accepted in most career fields. One thing I made a decision to do was stop at all my arm tats at my mid-forearm. The reason is even with long sleeve shirts, your cuff will move a little and expose any tattoos that go further than mentioned.
The most common reponse to tattoos if discovered by co-workers will be curiousity. I know when I started at my current job, I fully
planned on keeping all my tats secret. It is a very conservative enviroment. Then after only about 3 weeks, we had a tornado touch down about 300 yards away and destroy a neighboring building. Well, after the storm me and one another guy went out in the POURING rain and still 30+ mph wind to pull debris off and tape trash bags over the shattered rear windows of several of the girls' cars. Fully soak and freezing cold we both wrung out our shirts. And me (because I see them everyday) didn't think about my tattoos. Surprise!!! Would've been an understatement. Fortunately, everyone working that day was younger and pretty cool. I think they were so shaken up from the tornado and happy we were able to pull the debris off there cars that they'd have been happy to have anyone around that day. But since they found out after doing a "good deed" (which IMHO is just proper manners), I think it made people see PASSED the tattoos. If they had JUST SEEN the tattoos, I think the responses would have been more close-minded.
Anyway, in regards to the OP....
If you are asking others what you should have indelibly put on your skin IMHO you are not ready for this tattoo. Every tat on my body has personal meaning and is there everyday forever. In my case, the ideas kind of just come to me. And are linked to something going on in my life or at least inside my head. Then with the exception of the two that honor my deceased grandparents, I will dwell on the idea for a few months MINIMUM. (And sadly/honestly the ones for my grandparents I had started to plan when their health started declining. The only shock was that my grandma died first. Her heart gave out suddenly, we think from the stress of worrying about my grandpa who's health had been very poor for a couple years.)
In regards to military employment, the rules have changed lately. In the past the armed forces used to be very tolerant of tattoos but lately have been cracking down because of public opinion. (Which IMO is a dumb reason to do things in the military. Fear of public opinion is ONE OF the reasons we have not done what is needed WIN the current war. A war that has ran LONGER against a SMALLER enemy than all fronts of WWII.)
Ultimately, my advice is to wait. You will know what/if you want a tattoo for certain. The concern about not liking it when you're older hints uncertainty. (In reality if your 70 years old and your biggest concern in life is that your tattoo doesn't look as good as it did 45years ago... then you're life is pretty darn good!)
If you REALLY want it, nothing anyone says or does will change your mind. The design (which you should at least give the artist a BASIC idea for the theme) will come to you. As will size and placement. Furthermore, it is never a good idea to bargain hunt (you get what you pay for is true) or be turned off by having to wait (even several months) for an appointment. Good artists ARE hard to find, ARE booked in advance and ARE NOT cheap. Once you've decided completely on your own what you desire. Then
go for it wholeheartedly. Tattoos should never be done impulsively, intoxicated, to be cool or for anything other than a true personal desire to have it done. (Most tats people regret are done in such a manner.)
Best of Luck
-Ed