Welcome to the HOD Board - I think this is your first post! It is nice to meet you.

It sounds like your 3.5 yo has some good LA skills, which is wonderful!

All 3 of our sons actually knew all of their letters and most of their sounds at 3.5 yo when they did LHTH as well. LHTH is about much more than LA skills! It is about teaching Biblical history in chronological order, asking comprehension questions after you read the Biblical history, discussing devotional topics from the devotions, enjoying hands-on activities such as the art and the fingerplays, practicing large gross motor skills, etc. There is more to the math further into the guide. These skills are covered so nicely with LHTH's hands-on skills...
1 - patterns and colors
2 - patterns and counting
3 - sequencing letters and numbers (names and phone numbers)
4 - general measurement: comparing distances
5 - money: coin recognition
6 - counting steps
7 - comparing: few/many, once/more than once, tall/short
8 - ordinal numbers: first, second, third
9 - counting to 10: one to one correspondance
10 - patterns, shapes, counting
11 - general weight measurement: light/heavy
12 - auditory patterns
13 - comparing sizes: smallest/largest
14 - general length measurement: ordering longest to shortest
15 - matching and ordering by size: smallest to largest
16 - sorting and classifying
17 - counting, early addition/subtraction, zero
18 - counting, spatial terms, inside/outside
19 - duplicating patterns, spatial terms: away from
20 - counting and making sets
21 - tracing or copying designs and finding shapes
22 - counting: one to one correspondance
23 - comparing numbers: more than/less than/equal to
24 - counting and addition combinations that equal 5
25 - general measurement: area
26 - nonstandard measurement: “feet”
27 - sorting, counting, and graphing sets
28 - money: coin recognition, value, counting
29 - general time: yesterday, today, tomorrow
30 - number sense: more than 1 and counting forward/backward
31 - counting forward/backward and early addition
32 - general fractions: whole vs. part
33 - sorting and classifying: color, size, and shape
I would not do all of LHFHG with a 3.5 yo. However, to challenge your dd's LA skills, you can use the K LA resources from LHFHG right now. This is fun and easy to do.

Your dd can start phonics, maybe The Reading Lesson, as it does not require much writing. She can also start handwriting, using A Reason for HW K, or Italic A. If you are not using "The New Bible in Pictures for Little Eyes" for your Bible history in LHTH, I'd suggest using that for your dd rather than "A Child's First Bible." It has oral comprehension questions in it that are excellent to discuss. Either devotional in LHTH provides good reading and discussions - even our older dc enjoyed chiming in on their thoughts on the discussion questions or stories. You can certainly do both devotionals if you are wanting even more discussion. As far as read alouds, we just read aloud to our dc like you are doing. I'd not do LHFHG's Storytime yet, as the skills taught after the readings are appropriate for K or first grade. One other thing you can do is teach 2 LHTH lessons each day, one in the morning, and one in the afternoon. Then, when your dd finishes, she will be well prepared for LHFHG, and she will have had a super start to her homeschooling with LHTH! HTH!
In Christ,
Julie