"for years cannot be kept at bay,
and fading years will make you old;
then in their turn will men seem cold,
when you yourself are nipped and grey."
how do this affect the development of the poem's main theme?

The theme of Christina Georgina Rossetti's poem "Helen Grey" is, beauty isn't everything. We know this to be true because the Rossetti describes Helen Grey as "handsome" and "proud" but also says "But so you miss that modest charm / Which is the surest charm of all." This shows the reader that Helen Grey is very attractive and takes pride in her attraction. However, she has let her beauty go to her head, resulting in an unpleasant personality that no man has found her attractive. The last four lines of the poem "Helen Grey" support the its main theme by drawing the reader's attention to the reality of age and time. Time will continue to go by causing Helen to grow old, wrinkly, and gray. Time will pass and with it, Helen's beauty shall pass too. If she does not  change her ways, she will be left with and unattractive personality, and face.