I'm happy for you! The key things to remember:
1. Logistics - Identify which route you planned on taking.
2. Time - How long is your commute e.g., morning commute vs. afternoon commute
3. Dress appropriately based on the time of the year
4. Other cycling stuff - Headlight/tail light, bike bell instead of calling the passes (you don't have to have it now)
5. Hygiene - Do you have shower facilities/locker where you can store your biking stuff safely
6. Secure place to lock your bicycle
I started commuting last year and haven't looked back. I truly enjoy commuting regardless how hot, wet, or cold the day may be. However, I don't ride in the snow or ice; regardless how fast or slow I'm happy when I ride my bike! Btw, I commute 5 days per week and sometimes ride on the weekend as well.
I take a week break after 8 weeks of continuous riding just to break the monotony.
Additionally, riding a bike to work gives me positive outlook in life and relieves a lot of stress working and commuting.
It doesn't get any easier but I must say you'll get faster. There are days when I can pace myself to 3.15 minutes/per mile or simply ride at a leisurely pace.
I have a 12 year old bike and I must say it's not the bike, but it's the engine driving it. In other words, it helps you condition or acclimate your body to different type of riding fitness level. I've lost about 12 pounds since I started riding.
Happy riding.

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