My daughter is 26 months old and at 23 months (corrected age 21&1/2 months- EI uses corrected age until 2) had a 18 or so % delay(After they used the corrected age) and did not qualify for ST but did for OT. Your daughter is WAY ahead of even mine now! I made the mistake though of comparing my daughter to a friends daughter who is a month younger than mine. She talks full sentences and while it is not always clear you can make out her words with no problem.
My daughter can only sing weenawanda (ring around the) and oeoeoemoo moo mooo mooo mooo for Old McDonald. She counts to only 2 (but claps when we get to 5 or 10) and tries her ABCs but they are just sounds coming out while we say them to her. She claps at C. For thank you she says Nanu and signs it to us. She just started the Nanu this week. Please she signs and just started saying Pee for please. But she can say things like Dareitis (There it is) Googirbaby (good girl baby) and other common sentences we use. The only words that come out clearly are Baby, Mama and Dada. I am still not worried since the ST told us that as long as she is attempting the words even if they are not clear or pronounced correct they are making the sounds and it will all come together within a few - 6 months. So for 3 more months I will relax and continue to read and play with her interactive toys with her.
Remember that 5 months when they are this young can be a HUGE difference! That is like years of college! lol If you are really worried though definately contact your local Early Intervention office and have them do an evaluation. The eval is free and even if you do not qualify for services they will help you find ways to help your daughters speech along!
Good luck and blessings to you and yours!