I have the D3300 the D3400 is only a minor upgrade from it. I think you would find the image quality quite a lot better as it shares the 24mp sensor shared by the D5600 and D7200. Although I also own the D7200 I like the compactness of the D3300 the lens retracts to quite a short length and in normal conditions the images are as good as the D7200.
Hi Amanda - I, too, have a D3300 and second all that Richard has written. Something in the D7000 series will give you more focus points but will also be a heavier camera. The older I get the more I am thinking of mirrorless when I upgrade (ha ha). Can you possibly borrow or rent for the weekend the camera you are interested in? A branch of my local camera store has a rental department. Alternatively, invest in better glass.....