I am not really good at poetry,and I have to analayse the poem "Woman have loved before as I love now" by Millay,pls help, any analayse helpfull

Poetry is not that subjective and the subjectivity deals with slight variations that make the poem meaningful to different people in different ways.  It doesn't mean that you can't interpret poetry, and it doesn't mean that you can interpret it to mean anything you want.  And the fact that poetry is emotional certainly has nothing to do with whether or not it can be interpreted.  You don't have to have felt the exact same emotions a poet presents in order to understand those emotions.  That's one important role of literature:  to introduce readers to experiences they haven't had. 

That said, here's the poem:

Women have loved before as I love now;
At least, in lively chronicles of the past—
Of Irish waters by a Cornish prow
Or Trojan waters by a Spartan mast
Much to their cost invaded—here and there,
Hunting the amorous line, skimming the rest,
I find some woman bearing as I bear
Love like a burning city in the breast.
I think however that of all alive
I only in such utter, ancient way
Do suffer love; in me alone survive
The unregenerate passions of a day
When treacherous queens, with death upon the tread,
Heedless and willful, took their knights to bed.

The speaker is in the process of reading tales of women who have loved like she loves.  As she reads, she is

Hunting [for] the amorous line, skimming the rest,...

Looking for the romantic parts, she finds in literature the same feelings she feels, and thus knows that, at least in literature, women once loved as she loves.  The speaker feels an all-encompassing love and feels that no one else quite loves the way she does--who doesn't feel that when he/she is really in love?  This doesn't mean she's arrogant or full of herself.  It means she's in love. 

The speaker revels in a woman's right to love in the fashion of men, passionately and fully, not worrying about the consequences, as men have loved and been made heroes because of it throughout the centuries.  The speaker loves like a queen who has the power to do whatever she wants loves.  The speaker suggests that all women should love this way, as, at least stereotypically, men have been doing for thousands of years.