Hi. No need to worry, especially if you're sticking to the same airline the entire trip. :)
When you check your luggage in Boston, an employee will put a tag on it with your name and where your final destination and layover is it, so when you arrive in Atlanta and they take the luggage off that plane, it will be scanned and it will be put on your next flight. :)
Also since its your first time in an airport I'll give you a brief rundown of how everything works.
1) When you arrive in the airport, you will receive your tickets from a self kiosk. Make sure you have your confirmation number from booking your tickets, you will need it.
2) Check in your luggage.
3) Follow the signs to security check point. I recommend using the restroom on the way to the checkpoint in case the line gets backed up.
4) Go through security. Have your ID and boarding pass(ticket) ready to show to an officer. Once cleared, listen to the security if they are talking(they're most likely directing you which line to stand in). Remember to take off shoes, if you have any liquids then take it out your bag(leave them in the quart size bag though) and if you have a laptop then put it in a separate bin by itself.
5) Collect your stuff and check the monitors, your gate may have changed(PLEASE do this, almost missed my flight once from not doing this).
6) Chill until its boarding time. Flights board 30 minutes before departure time. I recommend being at the gate 35-40 minutes before departure time.
7) Board. Have your boarding pass ready and when your zone(it'll be on the pass) is called, line up, and once its scanned, you can go on then plane. :)
8) Arrive. Atlanta's airport can be chaotic since its huge. When you arrive, loom at your boarding pass for your Texas flight and look at the gate letter.(also check the monitors too though) You'll most likely land in a different concourse(same thing as terminal) then where your next departure flight will take off. If this happens, follow the signs to the other concourses then take the escalator to the subway. Get on the subway to your concourse.(or you can walk and look at the exhibits if you prefer to)
9) Go back up the escalator and shop and eat and enjoy the layover. :) The good thing about Atlanta's airport is that you can go to any concourse without going through security son feel free to roam different concourses if you have time.
10) Do the same thing as you did boarding the last plane.
11) Once you arrive in Texas, follow the signs to baggage claim. If you want something to eat or want to shop at the airport in Texas do it when you arrive, once you leave the terminal, you are not allowed to return.
12) When in baggage claim, check the monitors and find one that has the Delta Atlanta flight on it. Go that carousel and pick up your luggage.
13) Follow signs to ground transportation.
Have a fun and safe trip! :D x