That time on the bike computer or watch?
My commute is 4.3 and when I started it was about 25 minutes.
I can make it in between 18-20 depending on lights that I get caught at now. Timer on the computer only shows moving time on most. That's about 17-18 minutes most days for me.
You will get there in 2weeks or so if you stick to it.
I found a snack like a banana or some beef jerky in the late afternoon about an hour before the ride is helpful. Plenty of water with this heat!!! Start Hydrating a good 30 minutes before you head home in the afternoon.
Get the Polar insulated bottles...They are awesome Pack them with ice and you will get about 2 hours of cold.
I bought a cool 17 oz Thermos at Wally world for $10 this weekend that fits in the bottle holder. I bought it for getting my morning coffee to work (the guys at work make sludge and have to use creamer to get it down). Filled it with ice and water to test it out last night It held the ice for 5 hours (in the house). Got tired of waiting for it to melt so I poured it out.