Ode to Joy on Acoustic Guitar

I fail at the title of this blog post. We're learning guitar in music class...and I fail so badly. I can play the first line pretty much no problem...we only have to play lines 1 and 3 for the evaluation...because 1,2, and 4 are basically the same. I cannot play line three. I can play the first measure, I know it's third fret second string, third fret second string, open on first string, and then I think it's like first fret second string then isn't it like third fret second again, the first note in the second measure of the third line? Sorry if that's confusing to you. I really really love guitar, but I'm super slow at learning it and I fail at playing this third line...the evaluation is next Tuesday, I have just one more class before the evaluation, which really sucks, because I think I'll fail. And another part of the evaluation is playing the G scale, and then playing it backward. I didn't even try that yet... I had better not fail this class. I love the song and I think it sounds great...but I cannot play it. I'm so so bad at playing this third line of Ode to Joy, the second to fourth measures...I can't move my fingers between the strings that well - and it's only two strings! I suck at guitar, hahaha. And that's all we'll be doing the whole music class, pretty much. Sigh. I attached a YT vid of the song. I really wish I could play this good.