How many times have I been asked: How do you know if God is calling you? The question itself is indicative. How many people in the world, in our society, are even interested? God? He doesn't impact their lives. God? Does he even exist? And if so, why should they care.
If the feeling is there that it could be, it very well could be.
God does not hide himself - the search for one's vocation is not a game of hide and seek. He is careful, oh so careful, not to intrude on our freedom. But he still calls, a quiet thing, a gentle thing, a "what do you think" thing.
If you think you might be called, you probably are.
If that scares you, don't worry. Most people are afraid of things they are not familiar with. But God is amazing beauty, awesome charity, stunning goodness. In himself, he is love and he loves you personally. If you are called, you respond to that love by giving him absolutely everything.
Love is like that.
If the question is in your heart, follow it. It's the greatest adventure there can be.