Considering becoming vegan

I want to listen to both sides. So tell me your opinion so I dont regret adopting this diet.

Im sure that veganism as an idea is a good thing, that is what i believe, but the diet part is complicated a bit.

My family is against me, but they are becoming a little bit more accepting. I dont want to completely ignore their opinions so I told them if I ever become nutrient deficient I will drink milk and eat eggs. And if that isnt enough I will add meat (but reduce the amount). And so on.

I thought of following the vegan diet for 3 months straight then going for a vitamin b12, vit D, calcium, iron, zinc, omega 3 test. And see the results. If they are good, I will continue with the diet.

What do you guys think? Will this test be reliable? Considering that its fees are cheap but my family is stingy and wouldnt want me to keep on taking these test and the omega 3 test is expensive.