Code
LDA $19 BNE Continue
will go to Continue when $19 is nonzero. If $19 is zero, whatever code comes after it will be executed as though nothing happened.
Second, you seem to be confused on the workings of branching. A BEQ does not change the behavior of later BEQs, so the second BEQ in your code will never branch (if the condition to branch - $19 being 0 - was met, the one before would have branched past it). Instead it'll just continue into the youaresmall code (which is why it makes all forms of Mario jump higher). You should also know that the labels are just there for xkas to put things together with, and do not appear in the actual assembled code, so you don't need to branch into a label like you do before the Continue: label.
(I hope I'm explaining this all well enough...)