Normal, normal, normal. All those milestone ages are just averages, so while some kids hit them "early," others are "late." At this age, it doesn't mean that your child is advanced or delayed as long as they're within the range of typical development (which is usually pretty big).
Children often focus on one skill at a time, so while some are working on gross motor skills like crawling and walking, others are working on language or fine motor skills.
My oldest didn't crawl until nearly 10 months and didn't walk until 13 1/2 months, but she sat early (4 1/2 months) and focused a lot on fine motor skills. She also had huge language comprehension at a year (could follow 2-step instructions and identify books by their title), but was only saying 1-3 words. By age 2, her speaking and language comprehension were above average along with her fine motor skills, and her gross motor skills were right on track. She's now 7 years old and is still advanced in academics and is still right on track with gross motor skills. She will likely never be an athlete and isn't the fastest runner, but she did learn to ride a 2-wheeler last summer (at age 6), she can swim well enough to go off the diving board, and she won a hula-hoop contest at her school, so she clearly isn't lagging behind.
My other two children hit their milestones slightly differently, and they have different skill sets as well. Remember that like adults, all kids are different, and they'll have different strengths and weaknesses. While being "early" or "late" on a particular milestone may be an indicator of those strengths/weaknesses, it's simply too early to know for sure.
Sounds like your son is doing great!