It may be aluminium, steel, or something else. I don't feel its attraction to a magnet, but maybe it is because the keetle is too thin?
If it's stainless steel, it may not be very ferromagnetic. Try a very strong rare-earth magnet and test both the bottom and the sides, which may be made of different metals. If there is any attraction at all, the part is likely stainless steel.
If the kettle is quite light (not dense) and tapping the bottom or sides of the kettle makes a particularly dull sound, sort of a "tink", it is likely aluminum (Al). You can confirm this by putting a bit of sodium carbonate (washing soda) or sodium hydroxide (drain cleaner, caustic) solution in an inconspicuous place: if a gray discoloration develops, or bubbles come off, it's Al. N.B. This test will leave a permanent mark on aluminum, but so will washing with automatic dish-washing detergent, which is corrosive to Al.
Copper kettles have a reddish hue, and are more dense than Al.