I don't know much about group theory, but I think I am mathematically mature enough for a "rigorous" book.
– Jun 22 '19 at 20:07
https://math.stackexchange.com/questions/25506/introductory-group-theory-textbook
– JanJun 22 '19 at 20:11
If you haven't taken an abstract algebra course, it might be a good idea to grab an introductory undergrad text on that, such as Artin's Algebra, and read it's section on groups first. Plus such a text will also contain a general variety of applications of groups, for instance to Galois theory and to combinatorics (see the Pólya enumeration theorem).
– Kaj HansenJun 22 '19 at 20:18
For me, Gallian's Abstract Algebra text was a joy in the undergraduate course I took on the subject. Also, Fraleigh's text was a nice bridge for me between undergraduate and graduate level abstract algebra.
– DDSJun 23 '19 at 01:26