Battery was 2 years old and was replacing my iphone 6 battery so I figured I would do my wife's as well.
This did not go as smooth as the Iphone 6. The SE is more difficult mainly due to the location of the home button connector and how it is connected (metal shroud).
Also the iFixit Battery was a very tight fit and there was really no room left and right of the battery had to slowly pry it down and in.
Take it slow