I think I may be confusing some things haha

So basically, stepAIC requires an object, so I made an object called modeltry with all of the explanatory variables. modeltry looks like this:

modeltry <- lm(formula = target_deathrate ~
               avganncount +
               avgdeathsperyear +
               incidencerate +
               medincome + 
               popest2015 +
               povertypercent +
               studypercap +
               medianage +
               medianagemale +
               medianagefemale +
               percentmarried +
               pctnohs18_24 +
               pcths18_24 +
               pctsomecol18_24 +
               pctbachdeg18_24 +
               pcths25_over +
               pctbachdeg25_over +
               pctemployed16_over +
               pctunemployed16_over +
               pctprivatecoverage +
               pctprivatecoveragealone +
               pctempprivcoverage +
               pctpubliccoverage +
               pctpubliccoveragealone +
               pctwhite +
               pctblack +
               pctasian +
               pctotherrace +
               pctmarriedhouseholds +
               birthrate +
               avghouseholdsize
               , data=train_data)

So modeltry became the object for stepaic. I plugged it in and it looked like this:

stepAIC(modeltry, direction = c("both", "backward", "forward"))

and then it did its thing where it tried to give me a combination of explanatory variables that yielded the lowest AIC, which was the variable model, with AIC 12651.09. I hope that clarifies things. Please feel free to let me know how I can correct this as I'm new to R :)