I have a 13 month age gap. We're just a month in as the new baby is only a month old, but it's not as hard as I was expecting.
Keep the older one in childcare a day or two a week if you can. It keeps their routine that they're used to so it doesn't seem like everything changes for them because of the new baby. And it means you can get out to do some shopping or go to a baby group, it's much easier to do stuff when you just have one!
Get your house baby proofed and have somewhere safe you can set the older one if you need to for 5 or 10 minutes. We have a playpen so I can set the older one in there while I'm getting the pram out, sorting out the baby etc.
It will make your life easier if the older one is in a good bedtime routine and is sleeping well.
Get a good double pram, I take them out most days if I can for a walk, even if it's a short one.
The later stages of pregnancy were tough for me, I was working 3 days a week and was utterly exhausted, so much more than in my first pregnancy. Be realistic about how much you can take on and take any opportunity to get a rest.
It's all a bit hectic and my house is a mess but everyone is clean, fed and generally happy so that's an achievement!
You'll be absolutely fine. You'll spend most of your time running after your toddler and the baby will just fit in. The baby is the easy one, you'll wonder why you found it so hard with just one the first time round.
Congratulations, it really is lots of fun!