IMO this is a classic case of: "If you have to ask....."
Unless you are a seasoned DIYer with a good many electrical projects under your belt, AND have a very good grasp of electrical work in general, AND know the codes involved with doing this sort of job...you can do it yourself.
If you have to ask: "Can I do it?", the answer is usually probably not.
Doing a few jobs around the house is typically not a primer for doing a service change. And there are many important codes involved with such a project.
A panel change is often not a panel change but a service change. It is rare when just changing the panel makes sense.
Cost?
100 amps? 200 amps? Overhead? Underground?
A "typical" 200 amp overhead service with the run of the mill existing circuits will run you in the $1200-$2500 range. In your area I'd bet on the lower end of the scale.