Although you are allowed to promise her that you would consider marrying her when you are ready, she should not insist on calling you as if she were already married to you.

If she is the right person, why not marry her, if she is willing to accept you – even though your financial condition is not all that good? That is better than keeping her in limbo. Allah promises to help those who get married out of His bounty – if they do so with the sole intention of making themselves chaste.