If your soil is under 8.0 pH, it should be OK this year. The best thing to do is to do a soil test from an accredited lab. Most States have soil testing done by the state extension. Nebraska does not but a private soils lab does the testing inexpensively (about $10)
This would give you a true condition of your soil and also recommendations on what to do. I fight high pH and use elemental sulphur to help lower it. Both the soil test and addition of soil amendments are best at the end of the growing season but any time is better than never. Plant your tomatoes this year, see what happens and then go from there.
If you are going to direct sow tomatoes, there may not be enough time to get a good crop. I start seeds in March so the seedlings are established by planting time in May. Early girl is very commonly found at places that sell tomato plants, so I would suggest buying the plants this year and research growing tomatoes from seed for next year.
