There's lots we don't know about the speaker in "The Force…," but this much we do know: he's worked up. This speaker is feeling pretty passionate about the whole force thing, and his excitement is coming through loud and clear. Part of what makes the speaker seem so energetic is how the poem sounds (for more on this, check out the "Sound Check" section).
We also figure this guy is pretty young. After all, he's got all that aforementioned energy and passion. Plus, he refers to his "green age." With all the youthful, vital associations that go along with the color green, it's hard to imagine the speaker any other way. (Dying to know more about the color green? Check out our "Detailed Summary" section.)
Now, you might be thinking, "Thomas was young when he wrote this, and he seems like a pretty passionate guy. The speaker must be Thomas." Well, that may well be the case. There isn't anything in the poem to suggest otherwise. But remember, it's usually a good idea to separate the speaker from the poet. They aren't always one and the same. Suffice it to say that our speaker is filled with intense reflection, working through his thoughts about that all-powerful force in the universe: time.