OK first : such a cute story, I really loved it. It was sweet and I loved how the reader is dressed as a boy in general. But as for the critique.
first of all : punctuation is key. It's tedious and aggrivating to have to constantly go over your story for what seems to be simply punctuation, but it really gives an element of visualization to the reader. Especially since there'always more than one way to say things in the English language, so punctuation can really help directing the reader in the direction you want them to go.
That kind of leads me up to my next point of grammar. Make sure you have proper spelling and grammar in your story. That's another easy way to loose the reader or make them confused. It also really brings out your ideas when you use proper grammar. And as for proper spelling : if you spell a word wrong it could confuse the reader profoundly (being as there are such things as homophones).
Another big point is timing. With romances and lemons you have to remember that it takes time for people to finally fess up to their own feelings. If you're the kind of person who's inpatient with their writing then remember that you have time skips in your arsenal, they will really pay off in the long run.
Another thing to keep in mind is the attitude of the characters you are using. For the most part you were able to capture your characters attitudes, but you did have some instances when they acted very OOC (out of character), so that's another thing to keep in mind.
Don't forget to draw out certain events. Like the lemon bit for instance, personally I think it was a bit rushed, even though it was well written. Once again, moments when you just want to rush don't forget your time skips. Trust me, they will save your hide as a writer.
Now this last part is more of an optional piece of advice. And it is a more personal piece of advice, so feel free to just ignore it completely but try and make moods deeper. And what I mean like that is that : for instance, when the reader ran into Germany, instead of just talking and passing time try and say whether or not the two have them get along at all or something. Or another example is try to give said couple more intimacy, in doing so you make the reader feel more captivated in your story.
But overall it was a sweet story and I am anxious to see your stories from here on out. And I do hope you will take my words into consideration. Kelp up with the writing! XD!!!