Being Vegetarian, I’d definitely recommend taking B12, as this is quite hard to get enough from plant based foods (not impossible though) but its very important to not become deficient as it can lead to very serious forms of anaemia. The best type to take is Methyl – not cyanicobalamine, and consider sublingual or transdermal methods as apposed to tablets, as these enter straight into the blood stream..
I personally think vegetarians and vegans (ones who don’t just eat soy products or other processed foods) are getting more nutrition than most meat eaters, purely because of the higher intake of fruits and vegetables, not only vitamins and minerals, but also phytonutrients and antioxidents which are evry important to optimal health.. For me personally, to make sure, I do take extra supplements, as many of the soils are depleted in minerals such as selenium, so even eating a healthy varied plant based diet, its still easy to become deficient somewhere..
Try to choose supplements that have high quality food source nutrients in, as apposed to synthetic vitamins, and include lots of vitamin D.. A great source of info is Philip Day on this, or find a nutritionist who ypou trust to help advise you on getting what your body needs.. 🙂 Hope that helps