I’m also sorry for your loss.
Aside from the fact that you definitely should have an IRA at your age, I don’t know that you can stash $10K into it in a lump sum. (It has been many years since I started a new contributory IRA, but the rules used to be no more than $2000 per year, and it had to be “earned” income.)
In any case, I would definitely start an IRA and contribute the maximum that you can to it, as soon as you can. (You’ll find that having cash around will generate “needs” to spend it. Needs that didn’t even exist just weeks ago.)
When you’ve put what you can into an IRA (you don’t need to actually commit to a specific investment at this point), then you should place the balance into a taxable stock account.
I say this for one primary reason: Despite the recent and ongoing problems in the stock market, it has historically been and should continue to be the primary means (outside of massive inheritance and self-employment) to wealth for a majority of investors. It takes time, discipline and study, but you can manage to become wealthy (at least “comfortable”) by having your money work harder for you than you can.
When you have the balance in an account with a reputable discount broker then you need to start educating yourself about how and where to invest, and apply those lessons to your IRA. The money in your “cash” account can be replenished (or withdrawn) from time to time as you see fit, but the money you invest in the IRA can’t easily be withdrawn or added to, so you’ll want that investment to be somewhat more conservative and long-term.
But the lessons are good anywhere, any time.