Bathroom sink and toilet supply plumbing.

I bought the shut-off valves and stainless steel braided hose to connect the ½†galvanized plumbing in the wall to the bathroom sink hot/cold and the toilet. The ball valves I bought are ½†female (that will attach to the wall) and 3/8†male out. Is it okay to go from ½†to 3/8†– will I have flow problems? I can go ½ to ½, but I think I had ½ to 3/8 previously.
Thanks, Wayne

No problem. 3/8" will give you sufficient flow. Your sink pipes are probably only 3/8", and the toilet will fill nicely.

tubes

Even if you went 1/2 x 1/2 the tubes would still be the same sizes. 99.999+% of faucets and toilets are connected with valves like yours.