In the poem "Lines Composed a Few Miles Above Tintern Abbey," do you think the speaker regrets his loss of youth? Please explain within the context...

William Wordsworth's "Lines Composed a Few Miles Above Tintern Abbey," is a classic example of Wordsworthian Romanticism. It's also a long and complex poem, so it's perfectly fine to be confused by the subject matter. The most important thing to know about the poem is that it deals with memories of the past, wrestles with nostalgia, and tries to discern the benefits of experienced maturity over passionate youth. 

First, some context for the poem: the poem focuses on the speaker's return to a place of great natural beauty that he frequented when he was young. We learn that he has been away for quite some time, presumably living and working in an urban environment, and memories of his bucolic childhood have sustained him throughout this process. Naturally, this leads us to wonder if the speaker regrets his loss of youth. In order to answer this question, it's worth looking at a long quotation from the body of the poem:

                                            For nature then

(The coarser pleasures of my boyish days

And their glad animal movements all gone by)

To me was all in all.—I cannot paint

What then I was. The sounding cataract

Haunted me like a passion: the tall rock,

The mountain, and the deep and gloomy wood,

Their colours and their forms, were then to me

An appetite; a feeling and a love,

That had no need of a remoter charm,

By thought supplied, not any interest

Unborrowed from the eye.—That time is past,

And all its aching joys are now no more,

And all its dizzy raptures. Not for this

Faint I, nor mourn nor murmur; other gifts

Have followed; for such loss, I would believe,

Abundant recompense. (76-92)

These lines are central to the poem. In them, the speaker certainly glorifies his youth, reveling in the passion with which he engaged with nature. However, it's important to recognize that the narrator does not "faint" for the loss of his youth; indeed, "other gifts/ Have followed" and so there has been "abundant recompense" for the things that have been lost. 

Basically, the narrator says that, while he misses his youth, he has gained many beneficial things through the acquisition of age and maturity. As such, it would be inaccurate to say that the narrator "regrets" his loss of youth; it would be better to say that he looks back on his younger days with nostalgia, and uses them to better appreciate what he has accomplished in the time since leaving Tintern Abbey.