Sorry, but all those saying "hire an electrician" are either A- electricians that want to get paid or B - too scared of the "electrical magic" to take on something a little technical. 20 years ago I wired my entire home. I worked with city and L&I, followed a code book, and passed my inspection.

No disrespect to electricians. There are a lot of things in electrician world that are complicated and require specialized knowledge and experience. When it comes to a household panel swap, or a simple outlet replacement, 99% of the job is manual labor.

So, if you can do it legally (permits/inspections) and safely (disconnect power at meter) then go for it and don't let the A's or B's deter you.

Having said that, there is one additional thing to consider. Since you are replacing a panel, you are likely going to have to bring some items up to current code and not just replace new like the old. You will want to make sure you know what all is involved in said upgrade before starting.