According to Bitcoin Wiki:
A Bitcoin address, or simply address, is an identifier of 26-35 alphanumeric characters
Some Bitcoin addresses can be less than 34 characters (up to 26) and still be valid. A significant percentage of Bitcoin addresses are only 33 characters long, and some addresses can be even shorter. Each Bitcoin address represents a number. These shorter addresses are valid simply because they represent numbers that start with zeros, and when zeros are omitted, the encoded address becomes shorter.
So no, length does not imply higher / lower security.