I've traveled alone twice before for a little over a week on both occasions to Europe with only carry on.

This time I will be there for 3 weeks, and I don't think I'd manage to stuff enough in my carry on nor does the airline I am taking allow personal items (laptop, purse...) along with the c-on bag onboard.
I'm going on a small (183 passengers), yet full nonstop flight from JFK to BUD and I want to check my bag (1st time ever!) with my clothes.
I'm really uncomfortable with airports anyway, and checking is new to me. However, I love the idea of not fighting for overhead space and being a 5'2 weakling, lugging a 18-20 lb. bag and shoving it high up in the bin, with or without assistance, always makes me anxious.

Basically, I just want to know how likely is it that checked bags on an international nonstop flight are lost or delayed?
If so, what would cause a checked bag to be lost or delayed on a direct flight?

Any other checked baggage advice in general would be loved also.

Checking seems convenient to me [!!!!], however I don't want to purchase a new wardrobe in Europe if it mysteriously disappears.