Did Germany attack any US ships or attack any US interest before we entered the war?
Yes, the most famous being probably the sinking of the Reuben James
There was the sinking of the Reuben James, for one. The Reuben James was a destroyer assigned to convoy duty in the Atlantic. On October 31, 1945, the convoy it was guarding came across a wolfpack, and it was torpedoed and sunk by U-552. It was the first US naval vessel sunk in WWII.
That is, of course, October 31, 1941. The Germans weren’t sinking anything in October of '45.
The Reuben James was sunk in 1941. Didn’t WWII start in 1939?
Yes, but the question was about before “we” (meaning the U.S. in this case) entered the war, which wasn’t until December, 1941. (Admittedly, the header is confusing, but the actual OP is clearer.)
Yes, but the OP asked about attacks before the US entered the war – which was, of course, after ‘the day that will live in infamy’…
Dec 7, 1941. Pearl Harbour
Sorry for being unclear. I meant before the US entered the war not before the war started.
When did the US enter the European theater? And when did the US enter the African theater?
Lack of scrutiny, sorry.
8 dec 1941 - US declares war on Japan. Churchill informs the british parliament that Britain is at war with Japan
11 dec 1941 - Germany and Italy declare war on US and sign new millitary alliance with Japan
22 feb 1941 - formation of USA army bomber command to attack Germany.
Can’t find any more dates in The world at war
That was in 1942. You forget to increment the year.
This is the long version of the answer.
President Roosevelt declared a Neutrality Patrol on 9/5/1939, 4 days after the invasion of Poland, which was authorized to locate, track, and if necessary engage any belligerent air, surface, or submerged forces approaching US territorial waters. This authority was granted under the Neutrality Act of 1937.
One month later, the German pocket battleship Deutschland seized the US merchant City of Flint as a contraband carrier on its way to England. This seizure is sometimes cited as the first belligerent act against the US. The merchant City of Rayville was sunk by a German mine laid by a raider off Austrailia on 11/08/40, the first US ship sunk by Axis action.
In August of 1940, the Atlantic Charter is signed by Churchill and Roosevelt in Argentia Bay, Newfoundland. the first tangible result is the “Destroyers for Bases” agreement, transfering 50 mothballed US destroyers to the RN in return for 99-year leases on bases in the British West Indies.
The Neutrality Patrol is extended, and the Atlantic Fleet starts protecting convoys to Great Britain on March 1, 1941. The first encounter between USN forces and German submarines is on April 4, when the destroyer Niblack rescues survivors of a torpedoed Norwegian freighter and depth-charges the sub responsible. The attack fails, and neither the US nor the German vessel is damaged.
The first attack by a U-Boat on a USN ship is the attempted torpedoing of the USS Greer while it is serving as a convoy escort off Iceland on 9/4/1941. The Greer is not damaged. Roosevelt announces that the USN will attack any vessel threatening a US merchant or any merchant of any nation under US protection. In practice, this means that the USN has the authority to attack German raiders and U-Boats.
On 10/17/1941, the destroyer USS Kearny is torpedoed and damaged, with the loss of 11 killed and 22 injured. This is the first time a USN ship is damaged and American lives are lost to Axis forces.
On 10/30/1941, the fleet oiler USS Salinas is torpedoed and seriously damaged, and the next day sees the sinking of the USS Reuben James that others have referred to above. 100 lives are lost, and she is the first naval vessel lost to Axis action in WWII. Woody Guthrie writes a song about the sinking. Four other US merchant vessels are captured or sunk before 12/07/1941.
indeed I did. Apologies. 
They aided and abetted the enemy so they were open to a preemptive strike.
Hmm, where have I heard that before?
Although this is an obvious partisan snipe, the Battle of the Atlantic bears little resemblence to the run-up to the Second Gulf War. Note that American (merchant) vessels and lives had been lost to German forces prior to the signing of the Atlantic Charter. Also, there is no argument today, and very little argument at the time, that the German U-Boat forces were a direct threat to American lives and property. There is some debate as to whether Roosevelt overstepped the authority granted by the Neutrality Acts (probably), but not as to whether his actions were justified.
In short , it’s a parallel that just doesn’t hold up.