First off I am 5'7...I know for a girl that's not that short but for a model it is. Secondly I am a little bit curvier, I'm a size 4 which I'm willing to work on but it's going to be hard for me to drop to a size 2. Thirdly...I have tattoos. I have one rather large on my back:
Assuming you are over 18, you are too old to start modeling in high fashion. Girls start that at 14-15 and retire in their 20s, if they last that long. Plus your height and tattoos make that kind of modeling quite unlikely, if not impossible, especially at your age.
Even in lower tiers of modeling, such as catalog work, the tattoos especially are going to marginalize you in mainstream work. There would be oppertunities for some catalog work to be sure; a lot of stuff will hide the tattoos and your height and size would be fine as-is. But those aren't very high-paying jobs, and you'd have to work a lot to make any kind of money. Lots of catalog models have "day jobs."
You might also consider "fetish" modeling, which often does not require nudity, but will have you wearing "fetishy" costumes: leather, lingerie, stockings, etc. and possibly bondage-type photos (tied up, etc.). Many of the girls who do that are amateurs and the sessions can be scheduled around your other commitments.
Not sure about the tattoos. For most stuff I doubt it matters.
My wife regrets modelling, by the way. It tends to destroy the self esteem of most women involved.
It also pays horribly. Average full time female model in the us makes < 30k/year
A waitress who is hot enough to be a model, in the right environment, will make double or triple what an average model makes, and will be constantly told she is hot, instead of constantly being told she is too fat.
Well it's kind of like tennis - you can start this year but unless you are talented and hardworking in the extreme, you probably won't be beating Sharapova.
Modeling nowadays is a lot more diverse than it used to be, which can open niche opportunities in some markets.
You've certainly restricted your chances with tattoos, however I second what MrOracle had said in his 2nd paragraph about catalog modeling - plus general promotional / exhibit work.
Get a profile set up on ModelMayhem, make contacts, work on your portfolio, work on yourself. Nobody's going to give you a consideration because you are "willing to work on" your size 4 - get into your best possible natural shape NOW. It's a competitive area and you need to be pretty focused and self-motivated to succeed beyond what other people are willing to give you.
I have no experience in the modeling world so I don't know how much things like tattoos and size factor into your chance of making it, but I do know that your attitude and the amount of work you're willing to put in determines your success. Are there 5'7" models with tattoos? I bet you there is somewhere in the world so it's not impossible. More importantly, are you willing to Underfoe all the change necessary to become a model and stay one? You look great now, there's no need to change yourself. Have options, is modeling the only thing you're looking to do?
I think if you're talking about runway modeling, you're probably not what they generally look for due to your (very normal) height. But there are lots of different kinds of modelling, so pursue it if it's what you want but just make sure you don't pin all your hopes and dreams on it, have something else to fall back on.
I like your tats, but I'm pretty sure the runway model thing is not for you. They're incredibly picky about who they choose, and height and ink would be an issue. If you could find some type of alternative modeling, like something suicide girls related, I think that would be your best bet.
Not all alternative modeling is nudity required, so you could probably find some options out there.
ohhhhhhh yeah if you have tatoos your model career is screwed unless you pose for brands that are more liberal like West 49, Zero and etc you know what I mean? Where their brands are directed more to teenagers, that like rock and skateboard kind of thing, you feel me?
Modeling is a dirty bussiness you don't know what you're getting your self into. It might look nice and clean from the outside but when you get in it, it's not do clean. But opening an account in model meyham won't hurt. Modeling for fun, if you have a passion for it. But I wouldn't suggest you to become a professional model.
There are different types of models, not just the stick thin women.
Also, a lot of models get airbrushed in their photos. I knew a model that had a arm tattoo and it was removed during the airbrushing and photo editing. Has long has you have talent and a bubbly personality that is recognizable I am sure they will take you seriously.
There's a lot of models out there with curves so losing weight shouldn't be an issue. Yes 5"7 is on the shorter end for models but it's not completely unseen. The biggest issue you will have are tattoos. A lot of designers and photographers find them distracting and will not hire women who have them. You can try covering them for interviews/shoots with makeup, or look into alternative modeling where they are more widely accepted. Good luck :)