Dear Miriam,  

The fact of not yet finding the right man does not of itself indicate that you have a vocation.  

It may trigger the question in a different light and help you reflect, but if you accept a vocation it cannot be just by default, but because you discover that not finding the right man was God's providential way of making you understand that he wants you for himself, and therefore you give yourself to him totally and irrevocably, with all your heart and all your passion, with all your mind, strength and soul.  

This is important, because without this step of a firm, loving response to what you believe (i.e.: know through faith) he is calling you, any vocational option will always be in jeopardy, ready to be compromised as soon as Mr Right shows up. 

If you are capable with God's grace of such a decision you may have a vocation. But there are other factors involved as well that you would have to go over with a vocational director (not just a counselor, but someone who has experience in the spiritual life and has a good grasp of spiritual theology).  

If on the other hand you are reasonably and prudently sure that marriage is what you are called to, then do everything you can that will favor meeting Catholic men of your age who share your values. Involvement in community activities is one way, Catholic internet dating services is another. And pray. A good husband and a good marriage is a gift from God.  

God bless.