I don't think it would be too late, you will just have a later crop than others, perhaps look for an early variety and plant those so it takes less time to gain your yield.
You have plenty of time to plant your tomatoes. I love tomatoes (Have 32 plants in garden) and consider myself a tomato conisour(sp). Tomatoes are not going to do really well until it gets hot and humid. Don't wait to long though to get them in ground so that they can establish a good root system. Make sure to give them some fertilizer and water and plant them in a spot where they get plenty of sunshine (perferabley all day). Expect to be eating tomatoes by middle of July. Also, make sure you sucker the plants.
