Was this stupid or pointless?

[octop]

2/4 NL
Im in BB with 500
UTG has around 260 to start the hand
Table has been lose in calling raises and bets around 1/2-2/3 the size of the pot

I get JQ hearts UTG makes it 10 to go 4 callers I call

Flop 5 9 10 2 hearts ( 9 and 10 of hearts)
I check figuring UTG will bet 30-40 and get 1 or 2 callers then i will cr the field huge hoping to take it down.

UTG bets 100 into the 60ish dollar pot- WTF
Well I didnt think much and shoved- basically I had my mind made up about the big c/r and did not take into acount his bet size or his stack. (For example if he had a fullstack and had to call 300 more when I went all in and I might have some fold equity over an overpair. Being he only had to call 150 more I think I had 0 equity.)

How bad was my play? Was it incredibly stupid or just increasing my varience?