我现在比两年前高了.
I am taller than I was in two years ago.
I am taller than myself who was in two years ago.
都可以的I am taller than two years ago.这样行吗？可以的，没问题。
这样比较简洁。可是“I am taller than two years ago.”这句话的“than”后面没有人，这也行吗？这样是比较口语化地说法，因为这样说别人也可以看得懂。
当然你也可以写完整的表达：

I am taller than (I was in) two years ago.