I got puppies which I was so happy about, however, I got them both at the beginning of the summer (I'm a teacher) so I had all my time off and was able to take care of them. If it was this summer when I was taking grad classes, I wouldn't be able to do it!
That being said, I loved raising them from puppies, and seeing them grow and change
On the OTHER hand, I would love to rescue a dog. We applied to one rescue the October we got Nala and found out 7 months later we were accepted but that was after we decided on Nala. Older dogs are more set in their ways, you might be able to see their personalities a little bit more, and they may be potty trained.
Whatever you choose, you'll love him or her so much