Congrats, yes for me it took awhile before I was approved for a Target card, starting limit was also $300.00.
For the most part it was somehow very difficult for me to obtain a single Comentity credit line.
Suddenly something clicked on, and was approved for Target, VS, New York &Company, J Crew, and Forever 21.
Department store cards, I usually seldom would charge more than maybe $120.00 for an online purchase, and probably less in store.
Some would say I have too many Department store cards? I don't know.
It's just I like all of those stores.
Including my Belk, Gap, Lowes, Walmart, JC Penney, and Khols,
It can be addictive. I said I would stop when I hit the 40 mark. Then I applied for more and I now have 42 credit cards. Good luck to you. I am sure you are not done at the 5 though.