Header Lenght

I have a basic shotgun home, with 4 add-on's, 1 ea per side L/R, then 2 more back to back on the rear of the home. Kitchen is 12' X 9'4" Really narrow after you put cabinets in. I have a room beside it that I don't really use for anything. I want to remove the wall between the 2 rooms. Yes its the side of the house so its a supporting wall for the roof joist. Ceilings are only 7 foot tall (short) both rooms at same height between them. This room is 16' X 10' , This will give me the openess of kitchen that we want.
Anyone know if a 15 foot 4" I-BEAM would work for a header across this wall. I don't have much head space. This is an older house built with actual full 2 X 4 's rough cut lumber.