I recommend you replace that old gate valve with a ball valve, while you are there,
1-turn water off from meter
2-cut off gate valve
3-unsolder the tee from the nipple coming out the wall.
4 solder nipple under ball valve, ball valve m,then small nipple on top of valve
5- measure to nipple on top of ball valve, to bottom nipple out the wall
6-slide slip coupling over nipple on top of ball valve, (mark 1/2" away
) to know when you're in middle
7-solder tee and slide coupling up to solder
8-add adaptor to add hose bib ,
9-wipe it all down,
10-turn water back on SLOWELY and hope for the best
11-either open a beer and celebrate or open a yellow book and call a plumber